WAEC SSCE - Physics - 1990 (Objective)

A stone is dropped into the middle of a pool of water. Which of the following statements is/are correct? I, Spherical waves are set up in the water. II. The water moves outwards to the sides of the pool. III. Energy is transmitted outwards from the centre of disturbance

I only

II only

III only

I and III only Jibu sahihi

II and III only.

Maelezo ya Majibu

Soma maelezo ya somo kwenye Rectilinear Acceleration (WAEC)

Rectilinear Acceleration

Tazama Jibu

Swali 4 Ripoti

Which of the following is not a suitable method for reducing loss of heat from a piece of hot iron?

Wrapping it in cotton wool

painting it black Jibu sahihi

Placing it in a vacuum

Placing it on rubber supports

Keeping it in a closed wooden box

Maelezo ya Majibu

Soma maelezo ya somo kwenye Heat Transfer (JAMB)

Soma maelezo ya somo kwenye Heat Energy (WAEC)

Soma maelezo ya somo kwenye Work, Energy & Power (JAMB)

Soma maelezo ya somo kwenye Simple A.C Circuits (JAMB)

Soma maelezo ya somo kwenye Measurements And Units (JAMB)

Heat Transfer

Heat Energy

Work, Energy & Power

Simple A.C Circuits

Measurements And Units

Tazama Jibu

Swali 5 Ripoti

Which of the following pairs of light rays shows the widest separation in the spectrum of white light?

Yellow and red

Orange and green

Violet and blue

Blue and green

Red and indigo Jibu sahihi

Maelezo ya Majibu

Soma maelezo ya somo kwenye Light Energy (JAMB)

Light Energy

Tazama Jibu

Swali 6 Ripoti

An oscillating pendulum has a velocity of 2ms^-1 at the equilibrium position O and velocity at same point P. Using the diagram above, calculate the height of P above O. (Take g = 10ms²)

5.0m

2.0m

0.4m

0.2m Jibu sahihi

0.1m

Maelezo ya Majibu

To solve this problem, we need to use the conservation of mechanical energy of the pendulum. At the highest point P, the pendulum is momentarily at rest, and all its kinetic energy has been converted to potential energy. Therefore, the sum of kinetic and potential energies at P is equal to the sum of kinetic and potential energies at O. At position O, the pendulum has only kinetic energy, which is given by the formula 1/2 * m * v^2, where m is the mass of the pendulum and v is its velocity. We are not given the mass of the pendulum, but we can assume that it is constant throughout the motion. Therefore, the kinetic energy at O is 1/2 * m * (2)^2 = 2m. At position P, the pendulum has only potential energy, which is given by the formula m * g * h, where h is the height of P above O. Therefore, the potential energy at P is m * g * h. Since the total mechanical energy of the pendulum is conserved, we can equate the kinetic energy at O to the potential energy at P: 2m = m * g * h Simplifying this equation, we get: h = 2 / g = 2 / 10 = 0.2m Therefore, the height of P above O is 0.2m. Answer option (D) is correct.

Soma maelezo ya somo kwenye Scalars And Vectors (WAEC)

Soma maelezo ya somo kwenye Simple Harmonic Motion (WAEC)

Soma maelezo ya somo kwenye Gravitational Field (WAEC)

Scalars And Vectors

Simple Harmonic Motion

Gravitational Field

Tazama Jibu

Swali 7 Ripoti

A simple pendulum makes 50 oscillations in one minute. What is its period of oscillation?

0.02s

0.20s

0.83s

1.20s Jibu sahihi

50.00s

Maelezo ya Majibu

The period of a pendulum is the time it takes for one complete oscillation, which is the time it takes for the pendulum to swing back and forth once. In this question, we are given that the simple pendulum makes 50 oscillations in one minute. To find the period of oscillation, we need to divide the total time taken by the number of oscillations. We can convert one minute to seconds by multiplying it by 60, since there are 60 seconds in one minute. So, the time taken for 50 oscillations is: Time = 1 minute/50 oscillations = 60 seconds/50 oscillations = 1.2 seconds/oscillation Therefore, the period of oscillation of the pendulum is 1.2 seconds. Therefore, the correct option is (d) 1.20s.

Soma maelezo ya somo kwenye Simple Harmonic Motion (WAEC)

Simple Harmonic Motion

Tazama Jibu

Swali 8 Ripoti

The body P shown in the diagram above is in equilibrium. If the mass Q of the body is 10kg, calculate the tension T in the string. (Take g = 10ms²)

20/?3N

20N

50N

200?3N

200N Jibu sahihi

Maelezo ya Majibu

The body P is in equilibrium, which means that the net force acting on it is zero. The weight of P acts downwards and is balanced by the tension in the string acting upwards. The weight of P is given by: Weight of P = mP * g = 20 kg * 10 ms^-2 = 200 N Since the net force acting on P is zero, the tension in the string is equal to the weight of P. Therefore: Tension in string = Weight of P = 200 N So, option (E) is the correct answer.

Soma maelezo ya somo kwenye Equilibrium Of Forces (JAMB)

Soma maelezo ya somo kwenye Equilibrium Of Forces (WAEC)

Equilibrium Of Forces

Tazama Jibu

Swali 9 Ripoti

The diagram above represents a portion of a micrometer screw 20 gauge. What is its reading?

3.70mm

3.67mm

3.50mm

3.33mm

3.17mm Jibu sahihi

Maelezo ya Majibu

To determine the reading of the micrometer screw gauge, we need to add the main scale reading to the circular scale reading. From the image, we can see that the main scale reading is 3.0 mm, which is the distance shown between the left end of the sleeve and the central zero mark on the thimble. To find the circular scale reading, we count the number of divisions on the circular scale that line up with the main scale. We see that the 20th line on the circular scale is aligned with the main scale. Since each division on the circular scale represents 0.01 mm, we can calculate the circular scale reading as 20 x 0.01 mm = 0.20 mm. Therefore, the total reading is 3.0 mm + 0.20 mm = 3.20 mm. None of the answer options match our calculated value. The closest option is 3.17 mm.

Tazama Jibu

Swali 10 Ripoti

A tuning fork sounds louder when its stem is pressed against a table top than when held in air because

a larger mass of air is set vibrating by the table top

the whole table vibrates in resonance

the whole table has acquired a larger frequency Jibu sahihi

the fork and table have the same frequency

the amplitude of the vibrating fork is increased.

Maelezo ya Majibu

Soma maelezo ya somo kwenye Newton’s Laws Of Motion (WAEC)

Soma maelezo ya somo kwenye Rectilinear Acceleration (WAEC)

Soma maelezo ya somo kwenye Gravitational Field (WAEC)

Newton’s Laws Of Motion

Rectilinear Acceleration

Gravitational Field

Tazama Jibu

Swali 11 Ripoti

Which of the following statements about the atom is/are correct? I. Energy is needed to remove electrons from an atom II. Particles in the nucleus of an atom are bound together by strong forces. III. A large amount of energy is required to separate the particles in the nucleus of an atom. IV. When the nucleus of a uranium atom is split, the energy released accounts for the difference in the masses of the products and the parent nucleus

I only

I and II only

I and III only

II and IV only Jibu sahihi

I, II, III and IV

Maelezo ya Majibu

Soma maelezo ya somo kwenye Structure Of The Atom (Nigeria Only) (WAEC)

Structure Of The Atom (Nigeria Only)

Tazama Jibu

Swali 12 Ripoti

Which of the following is not crystal?

Sodium chloride

Lead Jibu sahihi

Copper (II) tetraoxosulphate (VI)

Glass

Germanium

Maelezo ya Majibu

Soma maelezo ya somo kwenye Structure Of The Atom (Nigeria Only) (WAEC)

Structure Of The Atom (Nigeria Only)

Tazama Jibu

Swali 13 Ripoti

The diagram above shows an incident ray A, inclined at angle of 50^o to the interface CB. The ray OB is found to lie along the surface. What is the refractive index of the medium X with respect to air?

sin50^o/sin40^o

sin40^osin50^o

sin90^o/sin50^o

sin40^o/sin90^o

sin90^o/sin40^o Jibu sahihi

Maelezo ya Majibu

Soma maelezo ya somo kwenye Refraction Of Light Through Plane And Curved Surfaces (JAMB)

Refraction Of Light Through Plane And Curved Surfaces

Tazama Jibu

Swali 14 Ripoti

A bat emits a sound wave at a speed of 1650.0ms^-1 and receives the echoes 0.15s later. Calculate the distance of the bat from the reflector

8.75m

16.50m

87.75m

123.75m Jibu sahihi

330.00m

Maelezo ya Majibu

The distance of the bat from the reflector can be calculated using the speed of sound and the time taken for the echo to return. The speed of sound is given as 1650.0ms^-1. When the bat emits a sound wave, it travels to the reflector and back, covering a total distance equal to twice the distance from the bat to the reflector. The time taken for this round trip is 0.15s (as given in the question). Using the equation: Distance = Speed x Time We can calculate the distance of the bat from the reflector as: Distance = (Speed of sound x Time taken)/2 Distance = (1650.0ms^-1 x 0.15s)/2 Distance = 123.75m Therefore, the correct answer is (d) 123.75m.

Soma maelezo ya somo kwenye Current Electricity (JAMB)

Soma maelezo ya somo kwenye Sound Waves (WAEC)

Current Electricity

Sound Waves

Tazama Jibu

Swali 15 Ripoti

An object R leaves a platform XY with a horizontal velocity of 7m^-1 and lands at Q. lf it takes the same object 0.3s to fall freely from Y to P, calculate the distance PQ.(Take g = 1Oms²)

7.30m

2.55m

2.10m Jibu sahihi

1.65m

0.45m.

Maelezo ya Majibu

The time of flight of an object in projectile motion can be calculated using the formula: t = 2u sin?/g where u is the initial velocity of the object, ? is the angle of projection, and g is the acceleration due to gravity. In this question, the object R leaves the platform with a horizontal velocity of 7m/s, which means its initial vertical velocity is 0. We can therefore use the formula: t = 2h/g where h is the height of the platform XY. We can rearrange this equation to solve for h: h = 1/2gt^2 We are given that it takes 0.3s for the object to fall freely from Y to P, so: h = 1/2 × 10 × (0.3)² = 0.45m Now, we can use the fact that the horizontal distance traveled by the object is given by: d = ut where d is the horizontal distance, u is the initial horizontal velocity, and t is the time of flight. Since there is no horizontal acceleration, the time of flight is the same as the time it takes for the object to fall from Y to P. Therefore: d = 7 × 0.3 = 2.1m Finally, we can use Pythagoras' theorem to find the distance PQ: PQ = ?(d² + h²) = ?(2.1² + 0.45²) ? 2.16m Therefore, the answer is 2.10m.

Soma maelezo ya somo kwenye Gravitational Field (JAMB)

Gravitational Field

Tazama Jibu

Swali 16 Ripoti

Calculate the current in the 3? resistor shown in
the diagram above.

3.0A

4.0A Jibu sahihi

4.3A

12.0A

39.0A

Maelezo ya Majibu

Soma maelezo ya somo kwenye Current Electricity (JAMB)

Soma maelezo ya somo kwenye Scalars And Vectors (JAMB)

Soma maelezo ya somo kwenye Simple A.C Circuits (JAMB)

Current Electricity

Scalars And Vectors

Simple A.C Circuits

Tazama Jibu

Swali 17 Ripoti

A parallel beam of light is to be obtained from the headlamp ofa car. At which of the following positions should the source of light be placed from the pole of its spherical minor?

At the focal point Jibu sahihi

At the centre of curvature

Beyond the centre of curvature

Between the focal point and the pole

Between the focal point and the center of curvature

Maelezo ya Majibu

In order to obtain a parallel beam of light from the headlamp of a car using a spherical mirror, the light source should be placed at the focal point of the mirror. This is because a spherical mirror can converge or diverge the light rays depending on where the light source is placed relative to the mirror. If the light source is placed at the focal point of the mirror, the light rays will be reflected in parallel to each other, creating a parallel beam of light. Placing the light source at any other position, such as the centre of curvature, beyond the centre of curvature, or between the focal point and the pole, will cause the light rays to converge or diverge, creating a beam of light that is not parallel. Therefore, the correct option is "At the focal point".

Tazama Jibu

Swali 18 Ripoti

Dry hydrogen is trapped by pellet of mercury in a uniform capillary tube closed at one end. If the length of the column of hydrogen at 27°C is 1.0m, at what temperature will the length be 1.20m?

22.5^oC

32.4^oC

77.0^oC

87.0^oC Jibu sahihi

360.0^oC

Maelezo ya Majibu

The problem involves a trapped gas at a fixed volume in a closed-end tube, and we are asked to find the temperature at which the length of the gas column will increase to a specified value. This can be solved using the relationship between the volume of a gas and its temperature, known as Charles's Law. According to Charles's Law, the volume of a gas is directly proportional to its temperature at constant pressure. Mathematically, this can be expressed as: V1/T1 = V2/T2 where V1 and T1 are the initial volume and temperature, respectively, and V2 and T2 are the final volume and temperature, respectively. In this problem, the volume of the gas is constant since it is trapped by the mercury pellet, so we can simplify the equation to: T1/T2 = L1/L2 where L1 and L2 are the initial and final lengths of the gas column, respectively. We are given that the initial length of the gas column is 1.0 m at a temperature of 27°C (which can be converted to 300.15 K). We are asked to find the temperature at which the length of the gas column will increase to 1.20 m. Using the above equation, we can solve for T2: T2 = (L2/L1) x T1 T2 = (1.20 m / 1.0 m) x 300.15 K T2 = 360.18 K We can convert this temperature to degrees Celsius by subtracting 273.15: T2 = 87.03°C Therefore, the correct option is (d) 87.0°C.

Soma maelezo ya somo kwenye Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

Tazama Jibu

Swali 19 Ripoti

sin50^o/sin40^o

sin40^osin50^o

sin90^o/sin50^o

sin40^o/sin90^o

sin90^o/sin40^o Jibu sahihi

Maelezo ya Majibu

Soma maelezo ya somo kwenye Refraction Of Light Through Plane And Curved Surfaces (JAMB)

Refraction Of Light Through Plane And Curved Surfaces

Tazama Jibu

Swali 20 Ripoti

Which of the following is not an evidence of the particle nature of matter?

Diffusion

Brownian motion

Diffraction Jibu sahihi

Crystal structure

Photoelectricity

Maelezo ya Majibu

Diffraction is not an evidence of the particle nature of matter. Diffraction is the bending of waves around an obstacle or through an opening. It is a property of waves, and it is not specific to the particle nature of matter. In fact, diffraction is often used to demonstrate the wave-like behavior of particles, such as electrons. On the other hand, the other options listed are evidences of the particle nature of matter: - Diffusion is the process of particles spreading out from an area of high concentration to an area of low concentration. It is a result of the movement of individual particles, and it is evidence of their particle-like nature. - Brownian motion is the random movement of particles in a fluid due to collisions with other particles. This motion is caused by the individual particles that make up the fluid, and it is evidence of their particle-like nature. - Crystal structure refers to the orderly arrangement of atoms or molecules in a solid. This structure is a result of the individual particles that make up the solid, and it is evidence of their particle-like nature. - Photoelectricity is the emission of electrons from a material when light shines on it. This phenomenon is evidence of the particle-like nature of light, which is made up of particles called photons. Therefore, the correct answer is "Diffraction".

Soma maelezo ya somo kwenye Structure Of The Atom (Nigeria Only) (WAEC)

Structure Of The Atom (Nigeria Only)

Tazama Jibu

Swali 21 Ripoti

Which of the following is/are necessary for the production of interference with two wave trains? I. The sources must be close to each other. II The waves must have the same frequency. III. The waves must have the same amplitude. IV. The waves must travel with the speed of light.

I, II and IV only

I, II and III only Jibu sahihi

I and II only

II, III and IV only

l, III and IV only

Maelezo ya Majibu

Soma maelezo ya somo kwenye Properties Of Waves: Reflection, Refraction, Diffraction (WAEC)

Soma maelezo ya somo kwenye Types Of Waves (WAEC)

Properties Of Waves: Reflection, Refraction, Diffraction

Types Of Waves

Tazama Jibu

Swali 22 Ripoti

What is the electric potential energy between two protons each of charge q and at a distance of r apart? (Permittivity of free space = ε_o)

4πε_oq²r

qr/4πε_o

q/4πε_or Jibu sahihi

q²/4πε_or

q 2 /4πε o r 2

Maelezo ya Majibu

Soma maelezo ya somo kwenye Electrostatics (JAMB)

Electrostatics

Tazama Jibu

Swali 23 Ripoti

The nucleon number and the proton number of a neutral atom of an element are 238 and 92 respectively. What is the number of neutrons in the atom?

330

165

146 Jibu sahihi

119

Maelezo ya Majibu

The nucleon number of an atom is the sum of its protons and neutrons. Therefore, the number of neutrons in an atom can be calculated by subtracting the number of protons (also called the atomic number) from the nucleon number. In this case, the nucleon number is given as 238 and the proton number (atomic number) is given as 92. Thus, the number of neutrons can be calculated as: Number of neutrons = nucleon number - proton number Number of neutrons = 238 - 92 Number of neutrons = 146 Therefore, the answer is 146.

Soma maelezo ya somo kwenye Structure Of The Nucleus (WAEC)

Structure Of The Nucleus

Tazama Jibu

Swali 24 Ripoti

A concave mirror of radius of curvature 20cm has a pin placed at 15cm from its pole. What will be the magnification of the image formed?

4.00

2.00 Jibu sahihi

1.33

1.50

0.25

Maelezo ya Majibu

When an object is placed in front of a concave mirror, the mirror forms an image of the object. The image can either be real or virtual, and it can be magnified or diminished depending on the location of the object and the focal length of the mirror. In this case, the concave mirror has a radius of curvature of 20cm, which means its focal length is half of that or 10cm. The pin is placed at a distance of 15cm from the pole of the mirror, which means it is located beyond the focal point. Since the object is placed beyond the focal point, the image formed will be real and inverted. The magnification of the image can be calculated using the formula: magnification = height of image / height of object = -v/u where v is the distance of the image from the mirror, u is the distance of the object from the mirror, and the negative sign indicates that the image is inverted. Using the mirror formula (1/f = 1/v + 1/u), we can find the distance of the image from the mirror: 1/f = 1/v + 1/u 1/10 = 1/v + 1/15 v = 30cm Now, we can use the magnification formula to find the magnification of the image: magnification = height of image / height of object = -v/u magnification = -30/15 magnification = -2.00 The negative sign indicates that the image is inverted, and the magnification is 2.00. Therefore, the answer is 2.00.

Tazama Jibu

Swali 25 Ripoti

A particle of mass 2.5 x 10^-6kg revolving around the earth has a radial acceleration of 4 X 10⁷ ms^-2. What is the centripetal force of the particles?

6.25 x 10^-14N

1.60 x10^-13N

5.00 x 10N

1.00x10²N Jibu sahihi

2.00x1O²N

Maelezo ya Majibu

Soma maelezo ya somo kwenye Newton’s Laws Of Motion (WAEC)

Newton’s Laws Of Motion

Tazama Jibu

Swali 26 Ripoti

A work of 30 joules is done is transferring 5 millicoulombs of charge from a point B to a point A in an electric Held. The potential difference between B and A is

1.7 x 10^-4V

3.4x10^-4V

1.5x10^-1V

6.0 x10³V Jibu sahihi

1.2 x10⁴V

Maelezo ya Majibu

The work done (W) in transferring charge (q) between two points in an electric field is given by the formula: W = qV Where V is the potential difference between the two points. In this question, the work done is 30 J and the charge transferred is 5 mC (or 5 x 10^-3 C). Therefore, we can rearrange the formula to find the potential difference: V = W/q = 30 J / 5 x 10^-3 C = 6,000 V So the potential difference between points B and A is 6,000 volts. Therefore, the correct option is: - 6.0 x 10^3 V

Soma maelezo ya somo kwenye Electrostatics (JAMB)

Electrostatics

Tazama Jibu

Swali 27 Ripoti

Calculate the resistance of the filament of a lamp rates 240 V, 40 W

240Ω

360Ω

720Ω

1440Ω Jibu sahihi

2880Ω

Maelezo ya Majibu

The power (P) of the lamp is given as 40 W and the voltage (V) is given as 240 V. Using Ohm's Law, we can calculate the resistance (R) of the filament of the lamp. Ohm's Law states that V = IR, where V is the voltage, I is the current, and R is the resistance. Using the formula for power, we know that P = IV. Substituting Ohm's Law into this equation gives P = (V²/R). Rearranging this formula gives R = V²/P. Substituting the given values gives R = (240²/40) = 1440 Ω. Therefore, the resistance of the filament of the lamp is 1440 Ω. Answer: 1440Ω

Soma maelezo ya somo kwenye Current Electricity (JAMB)

Current Electricity

Tazama Jibu

Swali 28 Ripoti

A cell of e.m.f. 1.5 V and internal resistance of 2.59 is connected in series with an ammeter of resistance 0.59 and a resistor of resistance 7.09. Calculate the current in the circuit.

0.15 A Jibu sahihi

0.20 A

0.60A

3.00A

6.67 A.

Maelezo ya Majibu

To calculate the current in the circuit, we need to use Ohm's law and Kirchhoff's circuit laws. First, we can calculate the total resistance of the circuit by adding the resistance of the ammeter and the resistor in series: R = 0.59 Ω + 7.09 Ω = 7.68 Ω Using Kirchhoff's circuit laws, we know that the current I through the circuit is equal to the e.m.f. E of the cell divided by the total resistance R of the circuit plus the internal resistance r of the cell: I = E / (R + r) Substituting the given values, we get: I = 1.5 V / (7.68 Ω + 2.59 Ω) = 0.15 A Therefore, the current in the circuit is 0.15 A. So, the answer is 0.15 A.

Soma maelezo ya somo kwenye Current Electricity (JAMB)

Soma maelezo ya somo kwenye Electric Cells (JAMB)

Soma maelezo ya somo kwenye Simple Harmonic Motion (WAEC)

Current Electricity

Electric Cells

Simple Harmonic Motion

Tazama Jibu

Swali 29 Ripoti

The eye defect illustrated by the diagram above is

astigmatism

long sightedness Jibu sahihi

loss accommodation

short sightedness

colour blindness

Maelezo ya Majibu

Soma maelezo ya somo kwenye Structure Of The Atom (Nigeria Only) (WAEC)

Structure Of The Atom (Nigeria Only)

Tazama Jibu

Swali 30 Ripoti

The eye defect illustrated by the diagram above is

astigmatism

long sightedness Jibu sahihi

loss accommodation

short sightedness

colour blindness

Maelezo ya Majibu

Soma maelezo ya somo kwenye Structure Of The Atom (Nigeria Only) (WAEC)

Structure Of The Atom (Nigeria Only)

Tazama Jibu

Swali 31 Ripoti

Given that the gravitational constant is 7 X 10^-11 Nm2kg^-2, what is the force of attraction between 10⁶kg mass of lead hanging one metre away from a 10³kg mass of iron?

7 x10^-20N

7 x 10^-5N

7x10^-2N Jibu sahihi

7x10³N

7x10⁰N

Maelezo ya Majibu

The force of gravitational attraction between two masses can be calculated using the formula F = G(m1m2)/r^2, where G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between their centers of mass. Using this formula, and plugging in the given values, we have: F = (7 x 10^-11 Nm^2/kg^2) x (10^6 kg) x (10^3 kg) / (1 m)^2 F = 7 x 10^-2 N Therefore, the force of attraction between the lead mass and the iron mass is 7 x 10^-2 N.

Soma maelezo ya somo kwenye Gravitational Field (JAMB)

Soma maelezo ya somo kwenye Gravitational Field (WAEC)

Gravitational Field

Tazama Jibu

Swali 32 Ripoti

Which of the following particles conduct electricity through salty water?

Atom

molecules

Electrons

Neutrons

Ions Jibu sahihi

Maelezo ya Majibu

Particles that conduct electricity through salty water are called ions. When salt is dissolved in water, it dissociates into positively charged ions (such as sodium ions) and negatively charged ions (such as chloride ions). These ions are able to move freely in the water, carrying an electric charge and allowing an electric current to flow through the solution. In contrast, atoms and molecules do not conduct electricity in water because they do not have a net electric charge and are not able to move freely. Electrons and neutrons are subatomic particles that can be found in atoms, but they are not able to move freely in water and therefore cannot conduct electricity in this medium. Therefore, the correct option is "Ions".

Soma maelezo ya somo kwenye Electrostatics (JAMB)

Electrostatics

Tazama Jibu

Swali 33 Ripoti

Which of the following is/are characteristics of sound? I Pitch II. Loudness III. Quality IV Noise

I only

II only

I and II only

l, II and III only Jibu sahihi

I, II, III and IV

Maelezo ya Majibu

Soma maelezo ya somo kwenye Current Electricity (JAMB)

Current Electricity

Tazama Jibu

Swali 34 Ripoti

What is the difference between a crystalline and an amorphous solid? A crystalline solid

has cubic structure while amorphous solid has hexagonal structure

has regularly-repeating pattern while an amorphous solid has not Jibu sahihi

is white while amorphous solid is yellow

is always hard while amorphous solid is always soft

melts on heating while an amorphous solid sublimates on heating.

Maelezo ya Majibu

The main difference between a crystalline and an amorphous solid is in their structure. A crystalline solid has a highly ordered, repeating pattern of molecules or atoms, which creates a well-defined shape and structure. This means that a crystalline solid has a regular geometric shape, with flat faces and sharp edges. On the other hand, an amorphous solid lacks this repeating pattern and does not have a well-defined shape. Instead, it has a more random arrangement of molecules or atoms, which creates a less ordered, less defined structure. This means that an amorphous solid has a more irregular shape, with rounded or curved surfaces. Examples of crystalline solids include diamonds, salt, and sugar, while examples of amorphous solids include glass, rubber, and plastic. In summary, the main difference between crystalline and amorphous solids is in their molecular or atomic arrangement, with crystalline solids having a highly ordered, repeating pattern and amorphous solids having a more random, less defined structure.

Soma maelezo ya somo kwenye Elasticity (JAMB)

Elasticity

Tazama Jibu

Swali 35 Ripoti

Water does not drip through an open umbrella of silk material unless the inside of the umbrella is touched. Which of the following phenomena is responsible for this?

Surface tension Jibu sahihi

Hydrostatic upthrust

Viscosity

Diffusion

Osmosis

Maelezo ya Majibu

The phenomenon responsible for water not dripping through an open silk umbrella is surface tension. Surface tension is the property of a liquid that causes its surface to behave like a stretched elastic membrane. The water droplets adhere to the silk fabric of the umbrella and are held in place by the cohesive forces between water molecules. The umbrella's fabric has a network of fibers, which creates capillary action that results in an upward force that balances the weight of the water, making it difficult for the water to fall through the umbrella. Only when the inside of the umbrella is touched and the tension is disrupted, the water droplets fall through the fabric.

Soma maelezo ya somo kwenye Measurements And Units (JAMB)

Measurements And Units

Tazama Jibu

Swali 36 Ripoti

Where will the image of the object OB shown in the diagram above be located after reflection from the mirror?

At F

Beyond C

Between O and P

Between P and F Jibu sahihi

Between F and C

Maelezo ya Majibu

Soma maelezo ya somo kwenye Electrostatics (JAMB)

Electrostatics

Tazama Jibu

Swali 37 Ripoti

Viscosity in a liquid does not depend on the

nature of the liquid

relative velocity between the liquid layers

area of the surfaces in contact

temperature of the liquid

normal reaction between the liquid layers Jibu sahihi

Maelezo ya Majibu

Viscosity is a measure of a liquid's resistance to flow, or how "thick" or "sticky" it is. The viscosity of a liquid depends on the nature of the liquid, the temperature of the liquid, and the relative velocity between the liquid layers. However, it does not depend on the area of the surfaces in contact or the normal reaction between the liquid layers. To put it simply, imagine you have two identical cups filled with the same liquid. If you pour the liquid from one cup to the other, you will notice that the liquid flows more slowly than water. This is because the liquid has a higher viscosity. The viscosity depends on the type of liquid (e.g. honey is more viscous than water), and how fast or slow the liquid is moving (e.g. syrup flows more slowly than water). The viscosity also changes with temperature, as higher temperatures tend to decrease the viscosity of a liquid. However, the area of the surfaces in contact and the normal reaction between the liquid layers do not affect the viscosity of a liquid. These factors might affect how the liquid flows, but they don't change the liquid's intrinsic property of viscosity.

Soma maelezo ya somo kwenye Pressure (JAMB)

Soma maelezo ya somo kwenye Liquids At Rest (JAMB)

Pressure

Liquids At Rest

Tazama Jibu

Swali 38 Ripoti

Two forces each of 4 N act on the opposite sides of a rectangular plate as shown in the diagram above. Calculate the magnitude of g the couple acting on the plate.

6.4 Nm

3.2 Nm

1.6 Nm Jibu sahihi

0.8 Nm

0.0 Nm

Maelezo ya Majibu

Soma maelezo ya somo kwenye Equilibrium Of Forces (JAMB)

Soma maelezo ya somo kwenye Equilibrium Of Forces (WAEC)

Equilibrium Of Forces

Tazama Jibu

Swali 39 Ripoti

A metal is illuminated with a radiation of energy 6.88eV If the kinetic energy of the emitted electrons is 1.5OeV, calculate the work function of the metal.

0.22eV

4.59eV

5.38eV Jibu sahihi

8.38eV

10.32eV

Maelezo ya Majibu

Soma maelezo ya somo kwenye Elementary Modern Physics (JAMB)

Elementary Modern Physics

Tazama Jibu

Swali 40 Ripoti

A radioactive substance has a half-life of 20 hours. What fraction of the original radioactive nuclei will remain after 80 hours?

1/32

1/16 Jibu sahihi

1/8

1/4

1/2

Maelezo ya Majibu

The half-life of a radioactive substance is the time taken for half of the radioactive nuclei to decay. After one half-life, half of the radioactive nuclei have decayed and only half remain. Similarly, after two half-lives, only a quarter of the original radioactive nuclei remain, and after three half-lives, only an eighth remain. In this question, the half-life is given as 20 hours, and the time elapsed is 80 hours, which is 4 times the half-life. Therefore, the number of half-lives that have passed is 4. So, after 4 half-lives, the fraction of the original radioactive nuclei remaining is (1/2) x (1/2) x (1/2) x (1/2) = 1/16. Therefore, the answer is: 1/16 of the original radioactive nuclei will remain after 80 hours.

Soma maelezo ya somo kwenye Wave-particle Paradox (WAEC)

Soma maelezo ya somo kwenye Properties Of Waves: Reflection, Refraction, Diffraction (WAEC)

Wave-particle Paradox

Properties Of Waves: Reflection, Refraction, Diffraction

Tazama Jibu

Swali 41 Ripoti

A rectangular coil of wire can rotate in a magnetic field. The ends of the coil are soldered to the two halves of a split ring. Two carbon brushes are made to press lightly against the split ring and when these are connected in circuit with a battery and rheostat, the coil rotates. This is a description of

a suspended- coil vanometer

a moving-cell ammeter

a d.c generator Jibu sahihi

an electric motor

an induction coil,

Maelezo ya Majibu

Soma maelezo ya somo kwenye Magnets And Magnetic Fields (JAMB)

Soma maelezo ya somo kwenye Gravitational Field (JAMB)

Magnets And Magnetic Fields

Gravitational Field

Tazama Jibu

Swali 42 Ripoti

When the direction of vibration of the particles of a medium is perpendicular to the direction of travel of a wave the wave transmitted is known as

sound wave

transverse wave Jibu sahihi

longitudinal wave

stationary wave

mechanical wave

Maelezo ya Majibu

The wave transmitted in which the direction of vibration of the particles of a medium is perpendicular to the direction of travel of the wave is called a transverse wave. In a transverse wave, the oscillations of the particles of the medium occur at right angles to the direction of propagation of the wave. Examples of transverse waves include waves on a string, electromagnetic waves, and seismic S-waves.

Soma maelezo ya somo kwenye Sound Waves (WAEC)

Soma maelezo ya somo kwenye Production And Propagation Of Waves (WAEC)

Soma maelezo ya somo kwenye Reflection Of Light At Plane And Curved Surfaces (JAMB)

Soma maelezo ya somo kwenye Properties Of Waves: Reflection, Refraction, Diffraction (WAEC)

Soma maelezo ya somo kwenye Simple A.C Circuits (JAMB)

Sound Waves

Production And Propagation Of Waves

Reflection Of Light At Plane And Curved Surfaces

Properties Of Waves: Reflection, Refraction, Diffraction

Simple A.C Circuits

Tazama Jibu

Swali 43 Ripoti

A force F is applied to a body P as shown in the diagram above. If the body P moves through a distance r, which of the following represents the work done?

F^cos?/_x

Fx tan?

Fx sin?

Fx cos? Jibu sahihi

Maelezo ya Majibu

Work done (W) is defined as the product of force (F) and displacement (s) in the direction of force. In the given diagram, the force F is acting at an angle ? to the direction of displacement, and the displacement is given by r. Therefore, the work done can be calculated as follows: W = F x r cos? Here, F represents the magnitude of the force, r represents the displacement of the body, and cos? represents the cosine of the angle between the force and displacement vectors. Therefore, the correct option for the work done is Fx cos?.

Soma maelezo ya somo kwenye Work, Energy And Power (WAEC)

Work, Energy And Power

Tazama Jibu

Swali 44 Ripoti

Heat transfer by convection in a liquid is due to the

translatory motion of the molecules of the liquid Jibu sahihi

increased vibration of the molecules of the liquid about their mean positions

expansion of the liquid as it is heated

latent heat of vaporization of the liquid

ability of the liquid to evaporate at all temperatures

Maelezo ya Majibu

Heat transfer by convection in a liquid is due to the translatory motion of the molecules of the liquid. When a liquid is heated, the molecules gain kinetic energy and move faster, which results in the formation of convection currents. These currents carry the heat energy from one point to another in the liquid. As the heated liquid rises, it transfers the heat to the surrounding cooler liquid molecules by collisions, causing the cooler liquid to become less dense and rise as well. This creates a continuous cycle of rising and sinking of the liquid, which transfers heat throughout the liquid. This process is known as convection, and it is the main mechanism of heat transfer in fluids like liquids and gases.

Soma maelezo ya somo kwenye Heat Transfer (JAMB)

Heat Transfer

Tazama Jibu

Swali 45 Ripoti

How much heat is given out when a piece of iron of mass 50g and specific heat capacity 460 Jkg^-1k^-1 cools from 85^oC to 25^oC?

1.38 x 10⁶ J

2.53x10⁴J

7.66x10³J

1.38x10³J Jibu sahihi

1.27 X10³J

Maelezo ya Majibu

The amount of heat given out by the iron can be calculated using the formula: Q = mcΔT Where Q is the heat energy transferred, m is the mass of the iron, c is the specific heat capacity of iron, and ΔT is the change in temperature of the iron. Substituting the given values, we have: Q = (0.05 kg) × (460 J/kg·K) × (85°C - 25°C) Q = 0.05 kg × 460 J/kg·K × 60°C Q = 1380 J Therefore, the amount of heat given out by the iron when it cools from 85°C to 25°C is 1380 J. Hence the correct option is (d) 1.38x10³J.

Soma maelezo ya somo kwenye Heat Energy (WAEC)

Heat Energy

Tazama Jibu

Swali 46 Ripoti

A cube made of a metal of linear expansivity is warmed through a temperature of t. lf the initial volume of the cube is V what is the increase in volume of the cube?

1/3α Vt

1/2α Vt

α Vt

2α Vt

3α Vt Jibu sahihi

Maelezo ya Majibu

Soma maelezo ya somo kwenye Thermal Expansion (JAMB)

Thermal Expansion

Tazama Jibu

Swali 47 Ripoti

Two solids P and Q of equal mass are heated to the same temperature and dropped simultaneously into two identical containers X and Y containing equal volumes of water at room temperature. The temperature of X will rise higher than that of Y only if the

volume of P is greater than that of Q

specific heat capacity of P is higher than that of Q Jibu sahihi

density of P is greater than that of Q

density of P is lower than that of Q

specitic heat capacity of P is lower than that of Q.

Maelezo ya Majibu

Soma maelezo ya somo kwenye Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

Tazama Jibu

Swali 48 Ripoti

A simple microscope forms an image twice the size of the object. If the focal length of the lens of the microscope is 20m, how far is the object from the lens?

10m

20m

30m Jibu sahihi

40m

60m

Maelezo ya Majibu

Soma maelezo ya somo kwenye Electrostatics (JAMB)

Electrostatics

Tazama Jibu

Swali 49 Ripoti

The absolute zero temperature is defined as the temperature at which

thermal motion ceases Jibu sahihi

the temperature of a gas is 273^oC

ice melts

the volume of a real gas is maximum

the pressure of a real gas is maximum

Maelezo ya Majibu

The absolute zero temperature is defined as the temperature at which thermal motion ceases. This is the lowest possible temperature that can be reached, and it is equivalent to zero Kelvin (0 K) or approximately -273.15 degrees Celsius (-459.67 degrees Fahrenheit). At this temperature, the particles that make up matter have the lowest possible energy and therefore stop moving completely. This is because temperature is a measure of the average kinetic energy of particles in a substance, and at absolute zero, the kinetic energy is zero. This concept is important in many areas of physics, such as thermodynamics and quantum mechanics, and it has practical applications in areas such as cryogenics, where temperatures approaching absolute zero are used to achieve superconductivity and other unique properties of matter.

Soma maelezo ya somo kwenye Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

Tazama Jibu

Swali 50 Ripoti

How long will it take to heat 3 kg of water from 28^oC to 88^oC in an electric taking a current of 6 A from an e.m.f. source of 220V?

96s

1.20s

570s Jibu sahihi

600s

1200s

Maelezo ya Majibu

To solve this problem, we need to use the formula: Q = m c ΔT where Q is the heat energy required to heat the water, m is the mass of the water, c is the specific heat capacity of water, and ΔT is the change in temperature. The specific heat capacity of water is 4.18 J/g°C, and since we have 3 kg of water, the mass of water is 3000 g. So, Q = 3000 g × 4.18 J/g°C × (88°C - 28°C) = 376440 J Now, we can use the formula for electrical energy: E = V I t where E is the electrical energy, V is the voltage, I is the current, and t is the time. Rearranging the formula to solve for t, we get: t = E / (V I) Substituting the given values, we get: t = 376440 J / (220 V × 6 A) = 570 s Therefore, the time it will take to heat 3 kg of water from 28°C to 88°C in an electric taking a current of 6 A from an e.m.f. source of 220V is 570 seconds or 9.5 minutes. So, the correct answer is 570s.

Soma maelezo ya somo kwenye Heat Energy (WAEC)

Soma maelezo ya somo kwenye Gravitational Field (JAMB)

Heat Energy

Gravitational Field

Tazama Jibu

Swali 51 Ripoti

Which of the following reduce(s) the effect of the back e.m.f. generated in the primary coil of an induction coil? The capacitor in the circuit II. The make and break contact in the circuit III. The ratio of turns in the secondary to that in the primary

l only

II only

I and II only Jibu sahihi

II and III only

I, II and III.

Maelezo ya Majibu

An induction coil is a device that converts high voltage, low current power to low voltage, high current power through electromagnetic induction. When an alternating current passes through the primary coil, a changing magnetic field is produced which induces an alternating current in the secondary coil. The back e.m.f. generated in the primary coil of an induction coil opposes the flow of current in the coil, causing a decrease in the current. This effect can be reduced by using a capacitor in the circuit, which stores the charge and releases it when the current drops. This maintains the flow of current and reduces the effect of the back e.m.f. Therefore, option I is correct. The make and break contact in the circuit also helps to reduce the effect of the back e.m.f. The contact repeatedly breaks the circuit, causing the current to stop flowing momentarily, which interrupts the magnetic field and reduces the back e.m.f. Therefore, option II is also correct. The ratio of turns in the secondary to that in the primary does not affect the back e.m.f. generated in the primary coil. It only affects the voltage induced in the secondary coil. Therefore, option III is incorrect. Hence, the correct answer is option C, I and II only.

Soma maelezo ya somo kwenye Capacitors (JAMB)

Soma maelezo ya somo kwenye Simple A.C Circuits (JAMB)

Capacitors

Simple A.C Circuits

Tazama Jibu

Swali 52 Ripoti

A charge of 1.0 x 10^-5 Coulombs experience force of 40N at a certain point in space. What is the electric field intensity?

8.00 x 10⁶NC^-1

4.00 x 10⁶NC^-1 Jibu sahihi

4.00 x 10^-4NC^-1

2.00 x 10^-4NC^-1

2.50 x 10^-1NC^-1

Maelezo ya Majibu

The electric field intensity (E) at a point in space is defined as the electric force (F) per unit charge (q) at that point. Therefore, we can use the formula: E = F/q Substituting the given values, we get: E = 40 N / 1.0 x 10^-5 C = 4.00 x 10⁶ N/C Thus, the electric field intensity at the given point in space is 4.00 x 10⁶ N/C. Therefore, the correct option is: 4.00 x 10⁶NC^-1.

Soma maelezo ya somo kwenye Electric Field (WAEC)

Electric Field

Tazama Jibu

Swali 53 Ripoti

A girl whose mass is 55kg stands on a spring - weighing machine inside a lift. When the lift starts to ascend, its acceleration is 2ms1. What will be the reading on the machine? (Take g = ms^-2)

66 kg Jibu sahihi

55 kg

44 kg

22 kg

11 kg

Maelezo ya Majibu

The reading on the spring - weighing machine will be greater than the actual weight of the girl. This is because when the lift starts to ascend, the girl and the weighing machine experience an upward force due to the acceleration of the lift. This force adds to the force of gravity acting on the girl and thus, the reading on the weighing machine increases. To find the reading on the weighing machine, we need to calculate the total force acting on the girl. Using Newton's second law, F=ma, the total force acting on the girl is the sum of the force of gravity and the force due to the lift's acceleration: F_total = (55 kg)(9.81 m/s^2) + (55 kg)(2 m/s^2) F_total = 676.05 N Therefore, the reading on the weighing machine will be: Reading = F_total = 676.05 N So the answer is 66 kg when converted to mass.

Tazama Jibu

Swali 54 Ripoti

lf the temperature of a small quantity of water in a closed container is gradually increased from 0^o to 40^oC then the density of the water within this range

increases for a while and then decreases Jibu sahihi

decreases for a while and then increases

increases gradually

decreases gradually

remains the same

Maelezo ya Majibu

The density of water decreases as its temperature increases from 0^oC to 4^oC, after which it increases. Therefore, as the temperature of the small quantity of water in a closed container is gradually increased from 0^oC to 40^oC, its density will first decrease until it reaches a minimum value at 4^oC, and then it will increase. Therefore, the correct answer is (A) "increases for a while and then decreases".

Soma maelezo ya somo kwenye Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

Tazama Jibu

Swali 55 Ripoti

Which of the following instruments is suitable for making the most accurate measurement of the internal diameter of a test tube?

metre rule

A pair of callipers Jibu sahihi

A micrometer screw gauge

A tape rule

A set square

Maelezo ya Majibu

Tazama Jibu

Swali 56 Ripoti

What is the value of R when G shows no deflection in the circuit illustrated above?

80?

75?

45?

20? Jibu sahihi

10?

Maelezo ya Majibu

Soma maelezo ya somo kwenye Electromagnetic Field (Part 2) (WAEC)

Soma maelezo ya somo kwenye Electromagnetic Field (Part 1) (WAEC)

Electromagnetic Field (Part 2)

Electromagnetic Field (Part 1)

Tazama Jibu

Swali 57 Ripoti

When the pressure of the gas in a discharge tube is gradually lowered. I. there is a violet glow in the tube II. the glow in the tube splits into bands which get further apart. III, the glow and the bands eventually disappear and there is a green fluorescence in the tube. IV. the tube breaks into pieces. Which of the following are correct?

I and II only

I and III only Jibu sahihi

I and IV only

I, II and III only

I, II III and IV

Maelezo ya Majibu

Soma maelezo ya somo kwenye Pressure (JAMB)

Soma maelezo ya somo kwenye Liquids At Rest (JAMB)

Pressure

Liquids At Rest

Tazama Jibu

Swali 58 Ripoti

Which of the following are contact forces? I. Force of tension II. Force of fiction, III. Magnetic force III Force of reaction.

I,II and III only

I, II and IV only Jibu sahihi

I, III and IV only

II, III and IV only

l and IV only.

Maelezo ya Majibu

Contact forces are forces that require physical contact between two objects to occur. Based on this definition, only forces of tension and friction are considered contact forces among the options given. Force of tension is a force that is transmitted through a string, rope, or cable when it is pulled tight by forces acting from opposite ends. It is a contact force because it requires physical contact between the string or cable and the objects pulling on it. Force of friction is a force that opposes motion between two surfaces in contact. It is a contact force because it requires physical contact between the two surfaces. Magnetic force and force of reaction are not contact forces because they do not require physical contact between two objects to occur. Magnetic force occurs between two magnetic objects, and force of reaction is the force exerted by a surface in response to an object pressing against it. Therefore, the correct answer is (b) I, II, and IV only.

Soma maelezo ya somo kwenye Temperature And Its Measurement (JAMB)

Soma maelezo ya somo kwenye Gravitational Field (WAEC)

Soma maelezo ya somo kwenye Equilibrium Of Forces (WAEC)

Temperature And Its Measurement

Gravitational Field

Equilibrium Of Forces

Tazama Jibu

Swali 59 Ripoti

A plane inclined at an angle at 30^o to the horizontal has an efficiency of 50%. The force parallel to the plane required to push a load of 120 N uniformly up the plane is

40√3N

60N

120N Jibu sahihi

200N

240N

Maelezo ya Majibu

Soma maelezo ya somo kwenye Motion (JAMB)

Soma maelezo ya somo kwenye Measurements And Units (JAMB)

Motion

Measurements And Units

Tazama Jibu

Swali 60 Ripoti