WAEC SSCE - Geography - 2009 (Essay)
Tambaya 1 Rahoto
(a) Draw a sketch map of Africa. On the map, mark and name:
(i) the Rivers Niger and Nile;
(ii) two areas of irrigation agriculture along each river.
(b) Outline three contributions of irrigation agriculture to any of the area shown in (a)(ii) above.
(c) Highlight three problems facing irrigation agriculture in the area chosen in (b) above.
(a) Sketch map of Africa showing the rivers and irrigation areas
Key locations marked on the sketch map:
- River Niger: Office du Niger irrigation scheme, Mali; and Baguinéda irrigation area, Mali.
- River Nile: Gezira irrigation scheme, Sudan; and the Nile Delta irrigation area, Egypt.
(b) Contributions of irrigation agriculture to the Gezira Scheme, Sudan
- It provides water for farming throughout the year and permits continuous or multiple cropping.
- It increases the production of food crops such as wheat, sorghum and vegetables for the growing population.
- It provides employment and income for farmers, farm labourers, traders and transport workers.
- It produces cash crops, especially cotton, which supply raw materials to industries and earn foreign exchange.
- It provides revenue to the government through taxes, export duties and sales of agricultural produce.
(c) Problems facing irrigation agriculture in the Gezira Scheme
- Salinisation and waterlogging: high evaporation and poor drainage leave salts in the soil and reduce soil fertility.
- High cost: canals, dams, pumps and irrigation equipment are expensive to construct, operate and maintain.
- Silting: silt deposited in canals and reservoirs reduces their depth and carrying capacity.
- Water-borne diseases: stagnant water in canals encourages diseases such as bilharzia and malaria.
- Fluctuation in water supply: low river flow or drought may reduce the amount of water available for irrigation.
Bayanin Amsa
(a) Sketch map of Africa showing the rivers and irrigation areas
Key locations marked on the sketch map:
- River Niger: Office du Niger irrigation scheme, Mali; and Baguinéda irrigation area, Mali.
- River Nile: Gezira irrigation scheme, Sudan; and the Nile Delta irrigation area, Egypt.
(b) Contributions of irrigation agriculture to the Gezira Scheme, Sudan
- It provides water for farming throughout the year and permits continuous or multiple cropping.
- It increases the production of food crops such as wheat, sorghum and vegetables for the growing population.
- It provides employment and income for farmers, farm labourers, traders and transport workers.
- It produces cash crops, especially cotton, which supply raw materials to industries and earn foreign exchange.
- It provides revenue to the government through taxes, export duties and sales of agricultural produce.
(c) Problems facing irrigation agriculture in the Gezira Scheme
- Salinisation and waterlogging: high evaporation and poor drainage leave salts in the soil and reduce soil fertility.
- High cost: canals, dams, pumps and irrigation equipment are expensive to construct, operate and maintain.
- Silting: silt deposited in canals and reservoirs reduces their depth and carrying capacity.
- Water-borne diseases: stagnant water in canals encourages diseases such as bilharzia and malaria.
- Fluctuation in water supply: low river flow or drought may reduce the amount of water available for irrigation.
Tambaya 2 Rahoto
Study the map extract on a scale of 1:50,000 and answer the following questions:
(a) Draw an outline of the area to a scale of 1:150,000
(b) On your outline, mark and name:
(i) a nodal settlement;
(ii) one secondary road;
(iii) the trigonometrical station northwest of Kaiama.
(c) Calculate the full length of River Gbesha in the north eastern part of the map from point X
(d) Identify: (i) two land use types in the mapped area;
(ii) three social amenities in Kaiama.
(a) Outline map reduced to a scale of 1:150,000
The reduction factor is:
\[\frac{1:150\,000}{1:50\,000}=3\]
Thus, every length on the original extract is reduced to one-third. The completed reduced outline is shown below.
(b) Features marked on the outline
- Nodal settlement: Kaiama. Several roads converge at Kaiama.
- Secondary road: No secondary road is shown on the map extract. The roads shown are the main road and minor roads or tracks.
- Trigonometrical station: the trigonometrical station northwest of Kaiama, marked by the trigonometrical-station symbol.
(c) Full length of River Gbesha from point X
Length measured along the winding river course on the map = \(27.4\text{ cm}\).
At a scale of \(1:50,000\):
\[\text{Ground distance}=27.4\times50,000=1,370,000\text{ cm}\]
\[\text{Ground distance}=\frac{1,370,000}{100,000}=13.7\text{ km}\]
Therefore, the full length of River Gbesha from X is 13.7 km.
(d) Identification
(i) Land-use types
- Agriculture or farming, indicated by scattered cultivation.
- Animal grazing, indicated by the savanna vegetation.
Other identifiable land uses include settlement and transportation.
(ii) Social amenities in Kaiama
- Postal agency
- Market
- Health centre
Other social amenities shown include a rest house, church and school.
Bayanin Amsa
(a) Outline map reduced to a scale of 1:150,000
The reduction factor is:
\[\frac{1:150\,000}{1:50\,000}=3\]
Thus, every length on the original extract is reduced to one-third. The completed reduced outline is shown below.
(b) Features marked on the outline
- Nodal settlement: Kaiama. Several roads converge at Kaiama.
- Secondary road: No secondary road is shown on the map extract. The roads shown are the main road and minor roads or tracks.
- Trigonometrical station: the trigonometrical station northwest of Kaiama, marked by the trigonometrical-station symbol.
(c) Full length of River Gbesha from point X
Length measured along the winding river course on the map = \(27.4\text{ cm}\).
At a scale of \(1:50,000\):
\[\text{Ground distance}=27.4\times50,000=1,370,000\text{ cm}\]
\[\text{Ground distance}=\frac{1,370,000}{100,000}=13.7\text{ km}\]
Therefore, the full length of River Gbesha from X is 13.7 km.
(d) Identification
(i) Land-use types
- Agriculture or farming, indicated by scattered cultivation.
- Animal grazing, indicated by the savanna vegetation.
Other identifiable land uses include settlement and transportation.
(ii) Social amenities in Kaiama
- Postal agency
- Market
- Health centre
Other social amenities shown include a rest house, church and school.
Tambaya 3 Rahoto
(a) Define ecosystem.
(b) Identify, with examples, two main components of the ecosystem.
(c) Describe the interdependence between the two main components identified, in (b) above.
(d) In what twc ways can environmental balance be achieved?
(a) Definition of ecosystem
An ecosystem is a natural unit in which living organisms (plants, animals and micro-organisms) interact with one another and with their non-living physical environment (soil, water, air, sunlight and climate) as a functioning whole through the flow of energy and the cycling of nutrients.
(b) Two main components of the ecosystem (with examples)
- Biotic (living) component - all living things in the ecosystem. Examples: green plants (producers), animals such as goats and lions (consumers), and bacteria and fungi (decomposers).
- Abiotic (non-living) component - the physical and chemical surroundings. Examples: sunlight, water, air, soil, temperature and mineral nutrients.
(c) Interdependence between the two components
- Green plants use sunlight, carbon dioxide from the air, and water and minerals from the soil to manufacture food by photosynthesis, so the biotic depends on the abiotic.
- Animals depend on plants and on other animals for food and on the air for oxygen.
- When plants and animals die, decomposers break down their remains and return nutrients to the soil and gases to the air, enriching the abiotic environment.
- Living organisms release carbon dioxide, water vapour and wastes that become part of the physical environment, while the physical environment supplies the energy, gases and nutrients that sustain life. Thus the two components depend on and influence each other continuously.
(d) Two ways environmental balance can be achieved
- Afforestation and reforestation - planting trees to replace those cut down maintains the natural vegetation, protects the soil and keeps the carbon and oxygen balance stable.
- Control of pollution and conservation of wildlife - reducing the discharge of harmful wastes into air, water and soil, and protecting animal species (for example through game reserves), keeps the food chains and nutrient cycles undisturbed.
Bayanin Amsa
(a) Definition of ecosystem
An ecosystem is a natural unit in which living organisms (plants, animals and micro-organisms) interact with one another and with their non-living physical environment (soil, water, air, sunlight and climate) as a functioning whole through the flow of energy and the cycling of nutrients.
(b) Two main components of the ecosystem (with examples)
- Biotic (living) component - all living things in the ecosystem. Examples: green plants (producers), animals such as goats and lions (consumers), and bacteria and fungi (decomposers).
- Abiotic (non-living) component - the physical and chemical surroundings. Examples: sunlight, water, air, soil, temperature and mineral nutrients.
(c) Interdependence between the two components
- Green plants use sunlight, carbon dioxide from the air, and water and minerals from the soil to manufacture food by photosynthesis, so the biotic depends on the abiotic.
- Animals depend on plants and on other animals for food and on the air for oxygen.
- When plants and animals die, decomposers break down their remains and return nutrients to the soil and gases to the air, enriching the abiotic environment.
- Living organisms release carbon dioxide, water vapour and wastes that become part of the physical environment, while the physical environment supplies the energy, gases and nutrients that sustain life. Thus the two components depend on and influence each other continuously.
(d) Two ways environmental balance can be achieved
- Afforestation and reforestation - planting trees to replace those cut down maintains the natural vegetation, protects the soil and keeps the carbon and oxygen balance stable.
- Control of pollution and conservation of wildlife - reducing the discharge of harmful wastes into air, water and soil, and protecting animal species (for example through game reserves), keeps the food chains and nutrient cycles undisturbed.
Tambaya 4 Rahoto
(a) Draw an outline map of Nigeria. On the map, locate and name:
(i) three major soil zones
(ii) an important crop associated with each zone;
(iii) an important town in any two of the zones
(b) Describe the characteristic features of any two of the soil zones shown in (a)(i) above.
(a) Outline map of Nigeria: soil zones, crops and towns
The map below shows three major soil zones and their associated crops. Kano and Ibadan are the two towns located in the northern sandy-soil zone and the southern forest-soil zone respectively.
| Soil zone | Main location | Associated crop | Town shown |
|---|---|---|---|
| Northern sandy soils | Far northern Nigeria | Groundnut | Kano |
| Interior lateritic soils | Middle Belt and inland areas | Yam | Makurdi |
| Forest soils | Southern Nigeria | Oil palm | Ibadan |
(b) Characteristic features of two soil zones
1. Northern zone of sandy soils
- It occurs mainly in the far northern part of Nigeria, where the climate is arid or semi-arid.
- It is formed under low rainfall and sparse vegetation.
- The soil is loose, friable and porous, with coarse sand grains and a sandy-loam texture.
- It is easy to cultivate and is generally well drained.
- It contains little humus and has low water-holding capacity, so it dries out rapidly.
- It is not heavily leached because rainfall is relatively low.
- It supports crops such as groundnut, millet, cotton and maize, especially where moisture is adequate.
2. Interior zone of lateritic soils
- It is widespread in the interior and Middle Belt of Nigeria.
- It develops under alternating wet and dry tropical conditions and is commonly reddish or brownish in colour.
- Its red colour results from iron compounds; it also contains aluminium compounds.
- It is heavily leached by rainfall and is therefore generally of medium fertility unless manure or fertiliser is added.
- It is sticky when wet but hard and compact when dry, and may become relatively impervious.
- It supports food crops such as yam, cassava, cocoyam and maize.
Bayanin Amsa
(a) Outline map of Nigeria: soil zones, crops and towns
The map below shows three major soil zones and their associated crops. Kano and Ibadan are the two towns located in the northern sandy-soil zone and the southern forest-soil zone respectively.
| Soil zone | Main location | Associated crop | Town shown |
|---|---|---|---|
| Northern sandy soils | Far northern Nigeria | Groundnut | Kano |
| Interior lateritic soils | Middle Belt and inland areas | Yam | Makurdi |
| Forest soils | Southern Nigeria | Oil palm | Ibadan |
(b) Characteristic features of two soil zones
1. Northern zone of sandy soils
- It occurs mainly in the far northern part of Nigeria, where the climate is arid or semi-arid.
- It is formed under low rainfall and sparse vegetation.
- The soil is loose, friable and porous, with coarse sand grains and a sandy-loam texture.
- It is easy to cultivate and is generally well drained.
- It contains little humus and has low water-holding capacity, so it dries out rapidly.
- It is not heavily leached because rainfall is relatively low.
- It supports crops such as groundnut, millet, cotton and maize, especially where moisture is adequate.
2. Interior zone of lateritic soils
- It is widespread in the interior and Middle Belt of Nigeria.
- It develops under alternating wet and dry tropical conditions and is commonly reddish or brownish in colour.
- Its red colour results from iron compounds; it also contains aluminium compounds.
- It is heavily leached by rainfall and is therefore generally of medium fertility unless manure or fertiliser is added.
- It is sticky when wet but hard and compact when dry, and may become relatively impervious.
- It supports food crops such as yam, cassava, cocoyam and maize.
Tambaya 5 Rahoto
(a) Name: (i) two major export items from your country
(ii) two major import items to your country
(iii) two major trading partners of your country.
(b) Highlight four benefits your country derives from trading with other countries
(c) Identify three problems encountered by your country in international trade.
Answer based on Nigeria as the candidate's country.
(a)(i) Two major export items
- Petroleum (crude oil)
- Cocoa (others include rubber, tin, columbite and natural gas)
(a)(ii) Two major import items
- Motor vehicles and machinery
- Electronics and food (rice) (others include tractors, computers and textiles)
(a)(iii) Two major trading partners
- China
- United States of America (others include Britain, Japan, Germany, Italy and South Korea)
(b) Four benefits from trading with other countries
- It provides foreign exchange for the country.
- It fosters international co-operation and friendly relations with other nations.
- It provides employment and generates revenue to government and income to individuals.
- It encourages specialisation in production and makes new products available, thereby improving the standard of living.
(c) Three problems encountered in international trade
- Inadequate foreign exchange and inadequate capital.
- High tariffs imposed on goods and low demand for the country's products abroad.
- Port congestion and the high cost of transportation (with smuggling and economic sabotage adding to the difficulties).
Bayanin Amsa
Answer based on Nigeria as the candidate's country.
(a)(i) Two major export items
- Petroleum (crude oil)
- Cocoa (others include rubber, tin, columbite and natural gas)
(a)(ii) Two major import items
- Motor vehicles and machinery
- Electronics and food (rice) (others include tractors, computers and textiles)
(a)(iii) Two major trading partners
- China
- United States of America (others include Britain, Japan, Germany, Italy and South Korea)
(b) Four benefits from trading with other countries
- It provides foreign exchange for the country.
- It fosters international co-operation and friendly relations with other nations.
- It provides employment and generates revenue to government and income to individuals.
- It encourages specialisation in production and makes new products available, thereby improving the standard of living.
(c) Three problems encountered in international trade
- Inadequate foreign exchange and inadequate capital.
- High tariffs imposed on goods and low demand for the country's products abroad.
- Port congestion and the high cost of transportation (with smuggling and economic sabotage adding to the difficulties).
Tambaya 6 Rahoto
(a) State four reasons for the concentration of manufacturing industries in the capital cities of Tropical African countries
(b) Give three reasons for the predominance of consumer oriented industries in Tropical Africa
(c) Describe three contributions of manufacturing industries to the economic development of Tropical African countries.
(a) Four reasons for the concentration of manufacturing industries in the capital cities of Tropical African countries
- Large market - capital cities have dense populations, giving industries a ready market for their products.
- Good infrastructure - they have better roads, rail, ports, water and electricity supply than other areas, which industries need.
- Availability of labour - both skilled and unskilled workers gather in the capital in search of jobs.
- Presence of capital and financial institutions - banks, government offices and investors are concentrated there, making it easy to raise funds.
- Nearness to government - being the seat of government they enjoy favourable policies, contracts and administrative attention.
(b) Three reasons for the predominance of consumer-oriented industries in Tropical Africa
- The economies are still developing and lack the heavy capital and technology needed for capital-goods industries, so light consumer industries are cheaper to establish.
- There is a large and growing population demanding everyday goods such as food, drinks, soap, textiles and footwear.
- Consumer industries use mostly local agricultural raw materials that are readily available.
- They require less skilled labour and yield quick returns on investment.
(c) Three contributions of manufacturing industries to economic development
- They create employment and raise the incomes and living standards of the people.
- They add value to local raw materials and reduce dependence on imported goods, saving foreign exchange.
- They diversify the economy away from over-reliance on agriculture and mineral exports.
- They generate revenue for government through taxes and stimulate the growth of towns and other supporting services.
Bayanin Amsa
(a) Four reasons for the concentration of manufacturing industries in the capital cities of Tropical African countries
- Large market - capital cities have dense populations, giving industries a ready market for their products.
- Good infrastructure - they have better roads, rail, ports, water and electricity supply than other areas, which industries need.
- Availability of labour - both skilled and unskilled workers gather in the capital in search of jobs.
- Presence of capital and financial institutions - banks, government offices and investors are concentrated there, making it easy to raise funds.
- Nearness to government - being the seat of government they enjoy favourable policies, contracts and administrative attention.
(b) Three reasons for the predominance of consumer-oriented industries in Tropical Africa
- The economies are still developing and lack the heavy capital and technology needed for capital-goods industries, so light consumer industries are cheaper to establish.
- There is a large and growing population demanding everyday goods such as food, drinks, soap, textiles and footwear.
- Consumer industries use mostly local agricultural raw materials that are readily available.
- They require less skilled labour and yield quick returns on investment.
(c) Three contributions of manufacturing industries to economic development
- They create employment and raise the incomes and living standards of the people.
- They add value to local raw materials and reduce dependence on imported goods, saving foreign exchange.
- They diversify the economy away from over-reliance on agriculture and mineral exports.
- They generate revenue for government through taxes and stimulate the growth of towns and other supporting services.
Tambaya 7 Rahoto
(a) Draw a sketch map of Africa. On the map, mark and name;
(i) Rivers Nile and Limpopo;
(ii) Lakes Victoria and Chad;
(iii) Namib and Kalahari deserts
(b) Outline four uses of rivers and lakes in Africa.
(c) Highlight four factors that limit the use of rivers in Africa.
(a) Sketch map of Africa
Key locations: River Nile is in north-eastern Africa and flows northwards to the Mediterranean Sea. River Limpopo is in south-eastern Africa and flows eastwards to the Indian Ocean. Lake Victoria is in East Africa near the Equator, while Lake Chad is in the north-central interior. The Namib Desert lies along the south-western coast, and the Kalahari Desert lies in the interior of southern Africa.
(b) Uses of rivers and lakes in Africa
- They provide water for domestic purposes such as drinking, cooking and washing.
- They provide water for irrigation and support livestock farming.
- They provide fish and employment in fishing, fish processing and boat building.
- They are used for inland water transport of people and goods.
- They are dammed for the generation of hydro-electric power.
- They supply water for industries and serve as tourist and recreational centres.
(c) Factors limiting the use of rivers and lakes in Africa
- Rapids and waterfalls interrupt river courses and hinder navigation.
- Seasonal fluctuations in water level cause some rivers to become shallow or dry up in the dry season, while flooding occurs in the wet season.
- Silting and sand bars, especially at river mouths, obstruct navigation.
- Aquatic weeds, such as water hyacinth, block waterways and hinder fishing and transport.
- Many rivers pass through sparsely populated, desert or otherwise unproductive areas, reducing their economic usefulness.
- Some rivers cross international boundaries, creating problems of joint control, development and use.
Bayanin Amsa
(a) Sketch map of Africa
Key locations: River Nile is in north-eastern Africa and flows northwards to the Mediterranean Sea. River Limpopo is in south-eastern Africa and flows eastwards to the Indian Ocean. Lake Victoria is in East Africa near the Equator, while Lake Chad is in the north-central interior. The Namib Desert lies along the south-western coast, and the Kalahari Desert lies in the interior of southern Africa.
(b) Uses of rivers and lakes in Africa
- They provide water for domestic purposes such as drinking, cooking and washing.
- They provide water for irrigation and support livestock farming.
- They provide fish and employment in fishing, fish processing and boat building.
- They are used for inland water transport of people and goods.
- They are dammed for the generation of hydro-electric power.
- They supply water for industries and serve as tourist and recreational centres.
(c) Factors limiting the use of rivers and lakes in Africa
- Rapids and waterfalls interrupt river courses and hinder navigation.
- Seasonal fluctuations in water level cause some rivers to become shallow or dry up in the dry season, while flooding occurs in the wet season.
- Silting and sand bars, especially at river mouths, obstruct navigation.
- Aquatic weeds, such as water hyacinth, block waterways and hinder fishing and transport.
- Many rivers pass through sparsely populated, desert or otherwise unproductive areas, reducing their economic usefulness.
- Some rivers cross international boundaries, creating problems of joint control, development and use.
Tambaya 8 Rahoto
(a) Describe any three of the following survey instruments:
(i) ranging poles; (ii) chain; (iii) cross staff; (iv) arrows.
(b) Outline the processes involved in carrying out a Chain Survey.
(a) Description of survey instruments (any three)
- (i) Ranging poles: straight wooden or metal poles about 2 to 3 metres long, painted in alternate bands of red and white (sometimes black) so that they are easily seen from a distance. They are pointed or shod with iron at the base to be stuck into the ground, and are used for marking survey stations and for ranging (keeping straight lines) during chaining.
- (ii) Chain: a measuring device made of a series of galvanised steel/iron links joined by rings, commonly the 20 m or 30 m chain, with brass tags/tallies at intervals to show the readings. It is used for measuring distances along the survey lines on fairly level ground.
- (iii) Cross staff: a small instrument (an octagonal box or frame with slits/sights, mounted on a pole) used to set out or measure right angles (offsets) from the chain line to features being surveyed.
- (iv) Arrows (chaining pins): pointed steel pins, usually a set of ten, with a ring at the top, used to mark the end of each chain length on the ground so that the number of chains measured can be counted.
(b) Processes involved in carrying out a Chain Survey
- Reconnaissance: walk over and study the area to be surveyed to plan the survey lines and station positions.
- Marking stations and drawing a key/index sketch of the framework of survey lines (well-conditioned triangles).
- Ranging the main (base/chain) line using ranging poles to keep it straight.
- Chaining the survey lines, measuring distances with the chain and inserting arrows at each chain length.
- Taking offsets to features on either side of the chain line using the cross staff/tape, and booking all measurements neatly in the field book.
- Applying check lines/tie lines to verify accuracy, then plotting the survey to scale in the office to produce the map.
Bayanin Amsa
(a) Description of survey instruments (any three)
- (i) Ranging poles: straight wooden or metal poles about 2 to 3 metres long, painted in alternate bands of red and white (sometimes black) so that they are easily seen from a distance. They are pointed or shod with iron at the base to be stuck into the ground, and are used for marking survey stations and for ranging (keeping straight lines) during chaining.
- (ii) Chain: a measuring device made of a series of galvanised steel/iron links joined by rings, commonly the 20 m or 30 m chain, with brass tags/tallies at intervals to show the readings. It is used for measuring distances along the survey lines on fairly level ground.
- (iii) Cross staff: a small instrument (an octagonal box or frame with slits/sights, mounted on a pole) used to set out or measure right angles (offsets) from the chain line to features being surveyed.
- (iv) Arrows (chaining pins): pointed steel pins, usually a set of ten, with a ring at the top, used to mark the end of each chain length on the ground so that the number of chains measured can be counted.
(b) Processes involved in carrying out a Chain Survey
- Reconnaissance: walk over and study the area to be surveyed to plan the survey lines and station positions.
- Marking stations and drawing a key/index sketch of the framework of survey lines (well-conditioned triangles).
- Ranging the main (base/chain) line using ranging poles to keep it straight.
- Chaining the survey lines, measuring distances with the chain and inserting arrows at each chain length.
- Taking offsets to features on either side of the chain line using the cross staff/tape, and booking all measurements neatly in the field book.
- Applying check lines/tie lines to verify accuracy, then plotting the survey to scale in the office to produce the map.
Tambaya 9 Rahoto
Write a geographical account of rail transport under the following headings:
(a) economic importance, (b) problems; (c) solutions
Rail Transport
(a) Economic importance
- Rail transport carries bulky, heavy and low-value goods, such as minerals, timber, cement, coal and agricultural produce, cheaply over long distances.
- It links settlements, regions, producing areas, markets, factories and ports.
- It conveys raw materials to industries and distributes finished goods to markets.
- It opens up previously inaccessible areas and encourages farming, mining, commerce and other economic activities.
- It carries large numbers of passengers, labourers and, where necessary, troops.
- It promotes national integration by linking different regions of a country.
- It aids the movement of ideas, innovations and culture between places.
- It provides employment for railway workers and promotes tourism.
- It generates income and revenue through passenger fares and freight charges.
- International rail links can promote trade and relations between neighbouring countries.
(b) Problems of rail transport
- Railway construction is very expensive, especially where bridges, tunnels, embankments and drainage works are required.
- There is often inadequate capital for rehabilitation, expansion and purchase of modern locomotives, coaches and spare parts.
- Poor maintenance leads to worn-out tracks, engines and coaches, frequent breakdowns and accidents.
- Inadequate management, poor planning and unreliable time schedules reduce efficiency and patronage.
- Narrow-gauge and single-track lines limit train speed, capacity and frequency of service.
- Steep gradients, rugged relief, swamps and rivers make construction and operation difficult.
- Flooding may wash away tracks or cause derailment where drainage is poor.
- Low technological development and shortage of skilled personnel hinder modern operation.
- Rail transport has fixed routes and cannot provide door-to-door service.
- It faces strong competition from road and air transport, resulting in low patronage on some routes.
- Vandalism and theft of railway equipment may interrupt services.
(c) Solutions to the problems
- Government and private investors should provide adequate funds, including bank loans where necessary, for railway development.
- Tracks, bridges, locomotives and coaches should be regularly maintained and worn-out parts replaced promptly.
- Modern locomotives, faster engines and improved passenger coaches should be provided.
- Railway managers should improve planning, scheduling, accounting and general management.
- Personnel should be properly trained and retrained in railway engineering, signalling, maintenance and administration.
- Uniform and wider gauges should be adopted to improve speed, safety and capacity.
- Single lines should be upgraded to double tracks on busy routes to allow trains to move in both directions without delay.
- Adequate drainage, culverts and embankments should be constructed to reduce flooding and overcome difficult gradients.
- Local manufacture or reliable supply of spare parts should be encouraged.
- Modern communication, signalling and security systems should be installed to reduce accidents, theft and vandalism.
- Rail services should be coordinated with road, water and air transport so that railways concentrate on heavy, bulky and long-distance traffic.
Bayanin Amsa
Rail Transport
(a) Economic importance
- Rail transport carries bulky, heavy and low-value goods, such as minerals, timber, cement, coal and agricultural produce, cheaply over long distances.
- It links settlements, regions, producing areas, markets, factories and ports.
- It conveys raw materials to industries and distributes finished goods to markets.
- It opens up previously inaccessible areas and encourages farming, mining, commerce and other economic activities.
- It carries large numbers of passengers, labourers and, where necessary, troops.
- It promotes national integration by linking different regions of a country.
- It aids the movement of ideas, innovations and culture between places.
- It provides employment for railway workers and promotes tourism.
- It generates income and revenue through passenger fares and freight charges.
- International rail links can promote trade and relations between neighbouring countries.
(b) Problems of rail transport
- Railway construction is very expensive, especially where bridges, tunnels, embankments and drainage works are required.
- There is often inadequate capital for rehabilitation, expansion and purchase of modern locomotives, coaches and spare parts.
- Poor maintenance leads to worn-out tracks, engines and coaches, frequent breakdowns and accidents.
- Inadequate management, poor planning and unreliable time schedules reduce efficiency and patronage.
- Narrow-gauge and single-track lines limit train speed, capacity and frequency of service.
- Steep gradients, rugged relief, swamps and rivers make construction and operation difficult.
- Flooding may wash away tracks or cause derailment where drainage is poor.
- Low technological development and shortage of skilled personnel hinder modern operation.
- Rail transport has fixed routes and cannot provide door-to-door service.
- It faces strong competition from road and air transport, resulting in low patronage on some routes.
- Vandalism and theft of railway equipment may interrupt services.
(c) Solutions to the problems
- Government and private investors should provide adequate funds, including bank loans where necessary, for railway development.
- Tracks, bridges, locomotives and coaches should be regularly maintained and worn-out parts replaced promptly.
- Modern locomotives, faster engines and improved passenger coaches should be provided.
- Railway managers should improve planning, scheduling, accounting and general management.
- Personnel should be properly trained and retrained in railway engineering, signalling, maintenance and administration.
- Uniform and wider gauges should be adopted to improve speed, safety and capacity.
- Single lines should be upgraded to double tracks on busy routes to allow trains to move in both directions without delay.
- Adequate drainage, culverts and embankments should be constructed to reduce flooding and overcome difficult gradients.
- Local manufacture or reliable supply of spare parts should be encouraged.
- Modern communication, signalling and security systems should be installed to reduce accidents, theft and vandalism.
- Rail services should be coordinated with road, water and air transport so that railways concentrate on heavy, bulky and long-distance traffic.
Tambaya 10 Rahoto
(a) Describe four characteristics of igneous rocks
(b) Using specific examples, state four ways in which metamorphic rocks are useful to man.
(a) Four characteristics of igneous rocks
- Crystalline: they are made of interlocking mineral crystals formed when molten magma or lava cooled and solidified.
- Non-stratified (no layers): they occur in solid masses without bedding planes or strata.
- Contain no fossils, because they were formed from molten material and never laid down as sediments.
- Generally hard, crystalline and non-porous, so they resist weathering; the crystals are large when the rock cooled slowly at depth (e.g. granite) and small/fine when it cooled quickly at the surface (e.g. basalt).
(b) Four ways metamorphic rocks are useful to man (with examples)
- Marble (from limestone) is used for building, floor and wall tiles, statues, monuments and decoration.
- Slate (from shale/clay) splits into thin sheets and is used for roofing, floor slabs and formerly writing boards.
- Quartzite (from sandstone) is very hard and is used as building stone, road-making aggregate and for making glass and abrasives.
- Graphite (from carbon-rich rock) is used for pencil leads, lubricants and electrodes; and gneiss is used as a durable building and paving stone (marble/graphite may also carry valuable minerals).
Bayanin Amsa
(a) Four characteristics of igneous rocks
- Crystalline: they are made of interlocking mineral crystals formed when molten magma or lava cooled and solidified.
- Non-stratified (no layers): they occur in solid masses without bedding planes or strata.
- Contain no fossils, because they were formed from molten material and never laid down as sediments.
- Generally hard, crystalline and non-porous, so they resist weathering; the crystals are large when the rock cooled slowly at depth (e.g. granite) and small/fine when it cooled quickly at the surface (e.g. basalt).
(b) Four ways metamorphic rocks are useful to man (with examples)
- Marble (from limestone) is used for building, floor and wall tiles, statues, monuments and decoration.
- Slate (from shale/clay) splits into thin sheets and is used for roofing, floor slabs and formerly writing boards.
- Quartzite (from sandstone) is very hard and is used as building stone, road-making aggregate and for making glass and abrasives.
- Graphite (from carbon-rich rock) is used for pencil leads, lubricants and electrodes; and gneiss is used as a durable building and paving stone (marble/graphite may also carry valuable minerals).
Tambaya 11 Rahoto
(a) With the aid of diagrams, describe the characteristics of any two of the following features:
(i) meanders; (ii) flood plain; (iii) braided stream.
Characteristics of any two river features (with diagrams)
(i) Meanders
- They are the wide, looping bends or curves of a river, well developed in the middle and lower courses where the valley is gentle and the river swings freely.
- Each bend has an outer (concave) bank that is steep and cut back by erosion (river cliff), where the current is fast and the water deep, and an inner (convex) bank that is a gentle, shelving slip-off slope where deposition takes place and the water is shallow.
- The river erodes sideways (lateral erosion), so meanders slowly grow and shift down-valley; when a loop is cut through at the neck it may be abandoned to form an ox-bow lake.
- Diagram: a plan view of a winding channel showing erosion on the outer bank and deposition (slip-off slope) on the inner bank.
(ii) Flood plain
- A flood plain is the wide, flat, low-lying area of land on either side of a river in its lower course, built up of alluvium (fine silt and mud) deposited when the river overflows its banks in flood.
- It is very fertile and level, and may carry features such as meanders, ox-bow lakes, and natural levees (raised banks of coarser material along the channel).
- It grows wider as the river shifts across it by lateral erosion and deposition, and is often used for farming and settlement.
- Diagram: a cross-section showing the river channel with levees, the flat alluvium-covered plain on both sides, and the valley bluffs at the edges.
(iii) Braided stream
- A braided stream is a river that splits into several separate channels which divide and rejoin around numerous islands or bars of sand and gravel, giving a plaited or interwoven appearance.
- It forms where the river carries a heavy load but has a variable or reduced discharge, so it drops the coarse material to build the mid-channel bars that force the water to divide.
- It is common on gentle gradients with easily eroded banks, for example near glacier snouts and on dry-region river beds.
- Diagram: a plan view showing one river dividing into interlacing channels around sand/gravel bars.
Bayanin Amsa
Characteristics of any two river features (with diagrams)
(i) Meanders
- They are the wide, looping bends or curves of a river, well developed in the middle and lower courses where the valley is gentle and the river swings freely.
- Each bend has an outer (concave) bank that is steep and cut back by erosion (river cliff), where the current is fast and the water deep, and an inner (convex) bank that is a gentle, shelving slip-off slope where deposition takes place and the water is shallow.
- The river erodes sideways (lateral erosion), so meanders slowly grow and shift down-valley; when a loop is cut through at the neck it may be abandoned to form an ox-bow lake.
- Diagram: a plan view of a winding channel showing erosion on the outer bank and deposition (slip-off slope) on the inner bank.
(ii) Flood plain
- A flood plain is the wide, flat, low-lying area of land on either side of a river in its lower course, built up of alluvium (fine silt and mud) deposited when the river overflows its banks in flood.
- It is very fertile and level, and may carry features such as meanders, ox-bow lakes, and natural levees (raised banks of coarser material along the channel).
- It grows wider as the river shifts across it by lateral erosion and deposition, and is often used for farming and settlement.
- Diagram: a cross-section showing the river channel with levees, the flat alluvium-covered plain on both sides, and the valley bluffs at the edges.
(iii) Braided stream
- A braided stream is a river that splits into several separate channels which divide and rejoin around numerous islands or bars of sand and gravel, giving a plaited or interwoven appearance.
- It forms where the river carries a heavy load but has a variable or reduced discharge, so it drops the coarse material to build the mid-channel bars that force the water to divide.
- It is common on gentle gradients with easily eroded banks, for example near glacier snouts and on dry-region river beds.
- Diagram: a plan view showing one river dividing into interlacing channels around sand/gravel bars.
Tambaya 12 Rahoto
(a) Draw a sketch map of Nigeria. One the map, mark and name:
(i) one cattle rearing zone;
(ii) one town in the zone;
(iii) using arrows, show the movement of cattle from the producing area to two consuming markets.
(b) Highlight three factors that favour cattle rearing in the area shown in (a)(i) above.
(c) Outline three problems of cattle rearing in the area shown in (a)(i) above.
(a) Sketch map of Nigeria showing cattle rearing and movement to markets
Key: The shaded northern savanna belt is the cattle-rearing zone. Kano is a town within the zone. The arrows show cattle moving southwards from Kano/the northern producing area to the major consuming markets of Lagos and Ibadan.
(b) Factors favouring cattle rearing in northern Nigeria
- The extensive Sudan and Sahel savanna grasslands provide abundant natural pasture for grazing cattle.
- The relatively dry climate and low humidity discourage the tsetse fly, thereby reducing trypanosomiasis.
- The broad, gently undulating plains provide wide open land for grazing and movement of herds.
(c) Problems of cattle rearing in northern Nigeria
- Rainfall is scanty and unreliable; consequently, pasture and surface water become inadequate during the long dry season.
- Overgrazing may destroy available pasture and lead to soil erosion and desertification.
- Diseases such as rinderpest and foot-and-mouth disease, together with inadequate veterinary drugs, vaccines and services, reduce cattle production.
Bayanin Amsa
(a) Sketch map of Nigeria showing cattle rearing and movement to markets
Key: The shaded northern savanna belt is the cattle-rearing zone. Kano is a town within the zone. The arrows show cattle moving southwards from Kano/the northern producing area to the major consuming markets of Lagos and Ibadan.
(b) Factors favouring cattle rearing in northern Nigeria
- The extensive Sudan and Sahel savanna grasslands provide abundant natural pasture for grazing cattle.
- The relatively dry climate and low humidity discourage the tsetse fly, thereby reducing trypanosomiasis.
- The broad, gently undulating plains provide wide open land for grazing and movement of herds.
(c) Problems of cattle rearing in northern Nigeria
- Rainfall is scanty and unreliable; consequently, pasture and surface water become inadequate during the long dry season.
- Overgrazing may destroy available pasture and lead to soil erosion and desertification.
- Diseases such as rinderpest and foot-and-mouth disease, together with inadequate veterinary drugs, vaccines and services, reduce cattle production.
Tambaya 13 Rahoto
(a) What is soil profile?
(b) Draw a well labelled diagram of soil profile.
(c) Describe the characteristics of the three zones of soil profile.
(a) Soil profile
A soil profile is a vertical section of soil from the ground surface down to the parent rock or bedrock, showing the different layers or horizons of the soil.
(b) Well-labelled diagram of a soil profile
(c) Characteristics of the three zones of a soil profile
- A horizon (topsoil or zone of eluviation)
- It is the uppermost layer of mineral soil, immediately below the surface litter.
- It contains decaying plant and animal remains which form humus.
- It is dark in colour and is usually the most fertile horizon.
- It is the zone of greatest biological activity, containing many soil organisms and most plant roots.
- Soluble minerals and fine materials are washed down from this horizon by percolating water.
- B horizon (subsoil or zone of illuviation)
- It lies below the A horizon and contains little humus.
- It is the zone in which clay, iron, aluminium and other mineral materials leached from the A horizon accumulate.
- It is often reddish, brownish or yellowish because of iron compounds.
- It is usually denser and more compact than the topsoil.
- Only deep-rooted plants commonly extend into this horizon.
- C horizon (parent-material horizon)
- It consists mainly of partly weathered rock fragments and other parent material from which the soil develops.
- It contains very little or no humus and has little biological activity.
- It is coarser and less developed than the A and B horizons.
- It grades downward into hard, unweathered bedrock.
Bayanin Amsa
(a) Soil profile
A soil profile is a vertical section of soil from the ground surface down to the parent rock or bedrock, showing the different layers or horizons of the soil.
(b) Well-labelled diagram of a soil profile
(c) Characteristics of the three zones of a soil profile
- A horizon (topsoil or zone of eluviation)
- It is the uppermost layer of mineral soil, immediately below the surface litter.
- It contains decaying plant and animal remains which form humus.
- It is dark in colour and is usually the most fertile horizon.
- It is the zone of greatest biological activity, containing many soil organisms and most plant roots.
- Soluble minerals and fine materials are washed down from this horizon by percolating water.
- B horizon (subsoil or zone of illuviation)
- It lies below the A horizon and contains little humus.
- It is the zone in which clay, iron, aluminium and other mineral materials leached from the A horizon accumulate.
- It is often reddish, brownish or yellowish because of iron compounds.
- It is usually denser and more compact than the topsoil.
- Only deep-rooted plants commonly extend into this horizon.
- C horizon (parent-material horizon)
- It consists mainly of partly weathered rock fragments and other parent material from which the soil develops.
- It contains very little or no humus and has little biological activity.
- It is coarser and less developed than the A and B horizons.
- It grades downward into hard, unweathered bedrock.
Tambaya 14 Rahoto
(a) Draw an outline map of West Africa. On it locate and name:
(i) one area of dense population;
(ii) one area of sparse population;
(iii) an important town in each area;
(iv) the River Niger
(b) Explain four factors that have led to the high density of population in the area shown on your map
(c) Highlight two problems of sparse population density
(a) Outline map of West Africa
The map shows:
- Area of dense population: south-western Nigeria (Yorubaland/Lagos area).
- Important town in the dense area: Lagos.
- Area of sparse population: northern Niger, within the Sahara Desert region.
- Important town in the sparse area: Agadez.
- River Niger: from the Guinea Highlands, through Mali and Niger, then south through Nigeria to the Gulf of Guinea.
(b) Factors responsible for the high population density in south-western Nigeria
- Favourable climate: The area has reliable rainfall, warm temperatures and a relatively humid environment, which favour settlement and agricultural production.
- Fertile soils and agriculture: Fertile soils support food crops and cash crops such as cocoa, kola nut, oil palm and vegetables. Intensive farming can therefore sustain a large population.
- Industrialisation and employment: Lagos and other towns contain factories, offices, markets, banks and transport businesses. These provide employment and attract migrants from other areas.
- Port and commercial functions: Lagos is a major coastal port and commercial centre. Import, export, shipping and trading activities encourage the concentration of people.
- Social amenities and transport: Good road and rail links, schools, hospitals, electricity, water supply and other services make the area attractive for settlement.
- Historical and administrative importance: The area has long been occupied and urbanised, while Lagos developed as an important colonial and administrative centre. This has encouraged continuous population growth.
(c) Problems of sparse population density
- Shortage of labour: There are too few workers to cultivate land fully, exploit mineral resources and undertake major development projects.
- High cost of providing services: Scattered settlements make roads, schools, hospitals, water supply and electricity expensive to provide; the small population also creates a limited market for goods and services.
Bayanin Amsa
(a) Outline map of West Africa
The map shows:
- Area of dense population: south-western Nigeria (Yorubaland/Lagos area).
- Important town in the dense area: Lagos.
- Area of sparse population: northern Niger, within the Sahara Desert region.
- Important town in the sparse area: Agadez.
- River Niger: from the Guinea Highlands, through Mali and Niger, then south through Nigeria to the Gulf of Guinea.
(b) Factors responsible for the high population density in south-western Nigeria
- Favourable climate: The area has reliable rainfall, warm temperatures and a relatively humid environment, which favour settlement and agricultural production.
- Fertile soils and agriculture: Fertile soils support food crops and cash crops such as cocoa, kola nut, oil palm and vegetables. Intensive farming can therefore sustain a large population.
- Industrialisation and employment: Lagos and other towns contain factories, offices, markets, banks and transport businesses. These provide employment and attract migrants from other areas.
- Port and commercial functions: Lagos is a major coastal port and commercial centre. Import, export, shipping and trading activities encourage the concentration of people.
- Social amenities and transport: Good road and rail links, schools, hospitals, electricity, water supply and other services make the area attractive for settlement.
- Historical and administrative importance: The area has long been occupied and urbanised, while Lagos developed as an important colonial and administrative centre. This has encouraged continuous population growth.
(c) Problems of sparse population density
- Shortage of labour: There are too few workers to cultivate land fully, exploit mineral resources and undertake major development projects.
- High cost of providing services: Scattered settlements make roads, schools, hospitals, water supply and electricity expensive to provide; the small population also creates a limited market for goods and services.
Tambaya 15 Rahoto
6. Use the statistics in the table below to answer the questions that follow:
| Months | J | F | M | A | M | J | J | A | S | O | N | D |
(a) Draw a Divergence Line Graph to represent the statistics.
(b) (i) Calculate the annual range of temperature.
(ii) State one other method of showing the statistics above.
(a) Divergence line graph
The monthly temperatures and their departures from the annual mean are:
| Month | J | F | M | A | M | J | J | A | S | O | N | D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temperature (°C) | 10 | 14 | 22 | 32 | 42 | 48 | 44 | 38 | 32 | 24 | 16 | 10 |
Annual mean temperature:
\[\bar T=\frac{10+14+22+32+42+48+44+38+32+24+16+10}{12}=\frac{332}{12}=27.7^\circ\text{C}\]
The bold horizontal line on the graph represents the mean temperature, or zero departure. Temperatures above it are positive departures and those below it are negative departures.
(b)(i) Annual range of temperature
\[\text{Annual range}=\text{temperature of hottest month}-\text{temperature of coldest month}\]
\[=48^\circ\text{C}-10^\circ\text{C}=\boxed{38^\circ\text{C}}\]
(b)(ii) One other method of showing the statistics is a simple bar graph.
Bayanin Amsa
(a) Divergence line graph
The monthly temperatures and their departures from the annual mean are:
| Month | J | F | M | A | M | J | J | A | S | O | N | D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temperature (°C) | 10 | 14 | 22 | 32 | 42 | 48 | 44 | 38 | 32 | 24 | 16 | 10 |
Annual mean temperature:
\[\bar T=\frac{10+14+22+32+42+48+44+38+32+24+16+10}{12}=\frac{332}{12}=27.7^\circ\text{C}\]
The bold horizontal line on the graph represents the mean temperature, or zero departure. Temperatures above it are positive departures and those below it are negative departures.
(b)(i) Annual range of temperature
\[\text{Annual range}=\text{temperature of hottest month}-\text{temperature of coldest month}\]
\[=48^\circ\text{C}-10^\circ\text{C}=\boxed{38^\circ\text{C}}\]
(b)(ii) One other method of showing the statistics is a simple bar graph.
Tambaya 16 Rahoto
(a) Draw an outline map of Nigeria. On the map, :how the annual distribution of rainfall
(b) Highlight three effects of rainfall on the distribution of vegetation in Nigeria.
(c) Describe four characteristics of the Guinea Savanna.
(a) Outline map of Nigeria showing annual rainfall distribution
Key: Annual rainfall generally decreases from the southern coast northwards. The Niger Delta and coastal belt receive over 2,000 mm; the southern interior receives 1,500 to 2,000 mm; the Middle Belt receives 1,000 to 1,500 mm; while the extreme north receives about 500 to 1,000 mm annually.
(b) Effects of rainfall on the distribution of vegetation in Nigeria
- Heavy and almost continuous rainfall, especially over 2,000 mm in the south, supports dense tropical rain forest with tall trees. In the coastal swampy areas, it also supports mangrove vegetation.
- Moderate rainfall of about 1,000 to 1,500 mm in the Middle Belt supports Guinea Savanna, made up of tall grasses and scattered trees.
- Low and seasonal rainfall in the north supports Sudan and Sahel Savanna, where vegetation consists mainly of short grasses, thorny shrubs and widely spaced drought-resistant trees. Thus, vegetation becomes shorter, less dense and more open from south to north as rainfall decreases.
(c) Characteristics of the Guinea Savanna
- It has tall grasses, often growing up to about 3 m high. The grasses are green in the rainy season and dry or brown in the dry season.
- It has few scattered trees, with open grassland between them.
- Many of the trees are deciduous and shed their leaves during the dry season; they commonly have thick bark and deep roots to withstand drought and bush fires.
- Gallery forests occur along river valleys and streams where moisture is available throughout much of the year.
Bayanin Amsa
(a) Outline map of Nigeria showing annual rainfall distribution
Key: Annual rainfall generally decreases from the southern coast northwards. The Niger Delta and coastal belt receive over 2,000 mm; the southern interior receives 1,500 to 2,000 mm; the Middle Belt receives 1,000 to 1,500 mm; while the extreme north receives about 500 to 1,000 mm annually.
(b) Effects of rainfall on the distribution of vegetation in Nigeria
- Heavy and almost continuous rainfall, especially over 2,000 mm in the south, supports dense tropical rain forest with tall trees. In the coastal swampy areas, it also supports mangrove vegetation.
- Moderate rainfall of about 1,000 to 1,500 mm in the Middle Belt supports Guinea Savanna, made up of tall grasses and scattered trees.
- Low and seasonal rainfall in the north supports Sudan and Sahel Savanna, where vegetation consists mainly of short grasses, thorny shrubs and widely spaced drought-resistant trees. Thus, vegetation becomes shorter, less dense and more open from south to north as rainfall decreases.
(c) Characteristics of the Guinea Savanna
- It has tall grasses, often growing up to about 3 m high. The grasses are green in the rainy season and dry or brown in the dry season.
- It has few scattered trees, with open grassland between them.
- Many of the trees are deciduous and shed their leaves during the dry season; they commonly have thick bark and deep roots to withstand drought and bush fires.
- Gallery forests occur along river valleys and streams where moisture is available throughout much of the year.
Tambaya 17 Rahoto
(a) (i) With the aid of a diagram, identify the main lines of latitude.
(ii) Calculate the distance between Addis Ababa in Ethiopia (latitude 10°N) and Maseru in Lesotho (latitude 30°S).
(b) (i) Define revolution of the earth.
(ii) Describe how revolution of the earth affects the length of day and night in the Northern Hemisphere.
(a) (i) Main lines of latitude
Lines of latitude are imaginary parallel circles drawn round the Earth and measured north or south of the Equator.
The main lines of latitude are:
- Arctic Circle, \(66\tfrac{1}{2}^{\circ}\text{N}\)
- Tropic of Cancer, \(23\tfrac{1}{2}^{\circ}\text{N}\)
- Equator, \(0^{\circ}\)
- Tropic of Capricorn, \(23\tfrac{1}{2}^{\circ}\text{S}\)
- Antarctic Circle, \(66\tfrac{1}{2}^{\circ}\text{S}\)
(a) (ii) Distance between Addis Ababa and Maseru
Latitude of Addis Ababa = \(10^{\circ}\text{N}\)
Latitude of Maseru = \(30^{\circ}\text{S}\)
Since the two towns are on opposite sides of the Equator:
\[\text{Difference in latitude}=10^{\circ}+30^{\circ}=40^{\circ}\]
\[1^{\circ}\text{ of latitude}=111\text{ km}\]
\[\text{Distance}=40\times111=4,440\text{ km}\]
Therefore, the distance between Addis Ababa and Maseru is \(4,440\text{ km}\).
(b) (i) Revolution of the Earth
Revolution is the movement of the Earth round the Sun in its orbit. The Earth completes one revolution in about \(365\tfrac{1}{4}\) days.
(b) (ii) Effects of revolution on the length of day and night in the Northern Hemisphere
- The Earth’s axis is tilted, and it remains inclined in the same direction as the Earth revolves round the Sun. Consequently, the length of day and night changes during the year.
- About 21 June, the Northern Hemisphere is tilted towards the Sun. It experiences summer, with longer days and shorter nights. At the Arctic Circle there is 24 hours of daylight, and areas north of it experience the midnight sun.
- About 22 December, the Northern Hemisphere is tilted away from the Sun. It experiences winter, with shorter days and longer nights. At the Arctic Circle there is 24 hours of darkness, while areas farther north may not see the Sun.
- About 21 March and 23 September, the Sun is overhead at the Equator. These are equinoxes, when day and night are approximately equal, each lasting 12 hours.
Bayanin Amsa
(a) (i) Main lines of latitude
Lines of latitude are imaginary parallel circles drawn round the Earth and measured north or south of the Equator.
The main lines of latitude are:
- Arctic Circle, \(66\tfrac{1}{2}^{\circ}\text{N}\)
- Tropic of Cancer, \(23\tfrac{1}{2}^{\circ}\text{N}\)
- Equator, \(0^{\circ}\)
- Tropic of Capricorn, \(23\tfrac{1}{2}^{\circ}\text{S}\)
- Antarctic Circle, \(66\tfrac{1}{2}^{\circ}\text{S}\)
(a) (ii) Distance between Addis Ababa and Maseru
Latitude of Addis Ababa = \(10^{\circ}\text{N}\)
Latitude of Maseru = \(30^{\circ}\text{S}\)
Since the two towns are on opposite sides of the Equator:
\[\text{Difference in latitude}=10^{\circ}+30^{\circ}=40^{\circ}\]
\[1^{\circ}\text{ of latitude}=111\text{ km}\]
\[\text{Distance}=40\times111=4,440\text{ km}\]
Therefore, the distance between Addis Ababa and Maseru is \(4,440\text{ km}\).
(b) (i) Revolution of the Earth
Revolution is the movement of the Earth round the Sun in its orbit. The Earth completes one revolution in about \(365\tfrac{1}{4}\) days.
(b) (ii) Effects of revolution on the length of day and night in the Northern Hemisphere
- The Earth’s axis is tilted, and it remains inclined in the same direction as the Earth revolves round the Sun. Consequently, the length of day and night changes during the year.
- About 21 June, the Northern Hemisphere is tilted towards the Sun. It experiences summer, with longer days and shorter nights. At the Arctic Circle there is 24 hours of daylight, and areas north of it experience the midnight sun.
- About 22 December, the Northern Hemisphere is tilted away from the Sun. It experiences winter, with shorter days and longer nights. At the Arctic Circle there is 24 hours of darkness, while areas farther north may not see the Sun.
- About 21 March and 23 September, the Sun is overhead at the Equator. These are equinoxes, when day and night are approximately equal, each lasting 12 hours.
