JAMB UTME - Physics - 1987 | Green Bridge CBT

Question 1 Rapport

A galvanometer of resistance $20\,\Omega$ is to be provided with a shunt that $\frac{1}{10}$ of the whole current in a circuit passes through the galvanometer. The resistance of the shunt is

2.00

Ω

2.22

Ω

18.00

Ω

18.22

Ω

Détails de la réponse

\frac{1}{10}

I x 20 =

\frac{9}{10}

I x Rs

Rs = 2.22 $Ω$

Lisez la note de cours sur Electrostatics (JAMB)

Electrostatics

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Question 2 Rapport

A wave has a frequency of 2Hz and a wavelength of 30cm. The velocity of the wave is

60.0ms-1

6.0ms-1

1.5ms-1

0.6ms-1

Détails de la réponse

V = F

λ

= 2 x 0.3

= 0.6ms-1

Lisez la note de cours sur Production And Propagation Of Waves (WAEC)

Production And Propagation Of Waves

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Question 3 Rapport

An elevator of mass 4800kg is supported by a cable which can safely withstand a maximum tension of 60 000N. The maximum upward acceleration the elevator can have is

2.5ms-2

5.0ms-2

7.5ms-2

10.0ms-2

Détails de la réponse

a =

\frac{F}{m}

= $\frac{60000 - (4800 \times 10)}{4800}$

= 2.5ms-2

Lisez la note de cours sur Newton’s Laws Of Motion (WAEC)

Newton’s Laws Of Motion

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Question 4 Rapport

A pool of water appears to be 1.0m deep when viewed vertically from above. If the refractive index of water is 1.33, what is the actual depth of the pool?

0.750m

1.013m

1.330m

13.3000m

Détails de la réponse

n =

\frac{real depth}{apparent depth}

1.33 = $\frac{real depth}{1}$

real depth = 1.33cm

Lisez la note de cours sur Refraction Of Light Through Plane And Curved Surfaces (JAMB)

Refraction Of Light Through Plane And Curved Surfaces

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Question 5 Rapport

If an object is placed in front of two mirrors inclined at 90o, how many images will be formed?

five

four

three

two

Détails de la réponse

n =

\frac{360}{θ}

- 1

= 360 - 1

= 3 images

Lisez la note de cours sur Electrostatics (JAMB)

Electrostatics

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Question 6 Rapport

The direction of the magnetic field at a point in the vicinity of a bar magnet is

always towards the north pole of the magnet

always away from the south pole of the magnet

along the line joining the point to the neutral point

in the direction the north pole of a compass needle would point

Magnetic Field (Part 1)

Electromagnetic Field (Part 2)

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Question 7 Rapport

The fig above represents the main sequence of energy conversion at Kainji dam. What is the efficiency of the system?

Q1/Q2

E/Q1

E/(Q1-Q2)

E/(Q1+Q2)

Heat Energy

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Question 8 Rapport

The fig above shows two connected bodies of masses M1 and M2 in equilibrium under gravity. The tension in the upper string is

(m1-m2)g

m1g

m2g

(m1+m2)g

Equilibrium Of Forces

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Question 9 Rapport

As a result of air at the top of a barometer, the height of the mercury column is 73.5cm when it should be 75.0cm; the volume of the space above the mercury is 8.0cm3. Calculate the correct barometer height when the barometer reads 74.0cm and the volume of the space above the mercury is 6.0cm3.

72.0cm

74.5cm

75.1cm

76.0cm

Détails de la réponse

Using, P1P1 = P2P2

(75 - 73.5) x 8 = (X - 74) x 6

X = 76cm

Lisez la note de cours sur Pressure (JAMB)

Pressure

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Question 10 Rapport

Calculate the amount of heat required to convert 2kg of ice at 2oC to water at 0oC. [specific heat capacity of ice = 2090Jkg-1oC-1, specific latent heat of fusion of ice = 333kJkg-1]

666J

8360J

666 000J

674 360J

Détails de la réponse

Q = mL + mc

θ

= (2 x 333000) + (2 x 2090 x 2)

= 674 360J

Lisez la note de cours sur Quantity Of Heat (JAMB)

Quantity Of Heat

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Question 11 Rapport

Hot water is added to three times its mass of water at 10oC and the resultant temperature is 20oC. What is the initial temperature of the hot water?

100oC

80oC

50oC

40oC

Détails de la réponse

Heat loss = heat gained

mh x ch x $θ$ h = mc x cc x $θ$ c

mh x ch x ( $θ$ - 20) = mc x cc x (20 - 10)

ch = cc ; mc = 3mh

therefore, $θ$ = 50oC

Lisez la note de cours sur Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 12 Rapport

When a transformer has more secondary windings than primary windings, it

has a smaller secondary current

has a greater power output

is a step-down transformer

increases the total energy output

Voir la réponse

Question 13 Rapport

Two capacitance of $6\,\mu\text{F}$ and $8\,\mu\text{F}$ are connected in series. What additional capacitance must be connected in series with this combination to give a total of $3\,\mu\text{F}$

3

μ

F

16

μ

F

24

μ

F

30

μ

F

Détails de la réponse

3 =

\frac{6 \times 8 \times c}{(6 \times 8) + (6 \times c) + (8 \times c}

therefore, C = 24 $μ$ F

Lisez la note de cours sur Capacitors (JAMB)

Capacitors

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Question 14 Rapport

An object 3.0cm high is placed 60.0cm from a converging lens whose focal length is 20.0cm. Calculate the size of the image formed

0.5cm

1.5cm

2.0cm

6.0cm

Détails de la réponse

F =

\frac{U V}{U + V}

20 = $\frac{60 \times V}{60 + V}$

V = 30cm

similarly, $\frac{U}{V}$ = $\frac{height of object}{height of image}$

$\frac{60}{30}$ = $\frac{3}{h}$

h = 1.5cm

Lisez la note de cours sur Light (JAMB)

Lisez la note de cours sur Measurements And Units (JAMB)

Light

Measurements And Units

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Question 15 Rapport

Four lenses are being considered for use as a microscope objective. Which of the following focal lengths is most suitable?

-5mm

+5mm

-5cm

+5cm

Electromagnetic Waves: Types Of Radiation In Electromagnetic Spectrum

Light Waves

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Question 16 Rapport

he coefficient of static friction between a 40kg crate and concrete surface is 0.25. Find the magnitude of the minimum force needed to keep the crate stationary on the concrete base inclined at 45o to the horizontal. [G = 10ms-1]

400N

300N

283N

212N

Détails de la réponse

momentum force = R5n

θ

-

μ

Rcos

θ

Fm = (40 x 10 x sin 45) - (40 x 10 x 0.25 x cos 45)

= 212N

Lisez la note de cours sur Friction (JAMB)

Friction

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Question 17 Rapport

Which of the following units is equivalent to kgms-1?

Ns-1

Nms-1

Ns

Js-1

Détails de la réponse

kgms-1 =

\frac{m a s s}{d i s t a n c e}

since, F = ma = kgms-1 = N

kgms-1 = Ns

Lisez la note de cours sur Measurements And Units (JAMB)

Measurements And Units

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Question 18 Rapport

In the above, a voltage V is applied across the terminals P and Q. The voltage across the 1 ohm resistor is

V/8

V/4

V/3

V/2

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Question 19 Rapport

A load of 5N gives an extension of 0.56cm in a wire which obeys Hooke's law. What is the extension caused by a load of 20N?

1.12cm

2.14cm

2.24cm

2.52cm

Détails de la réponse

\frac{F_{1}}{e_{1}}

=

\frac{F_{2}}{e_{2}}

$\frac{5}{0.56}$ = $\frac{20}{e_{2}}$

e2 = 2.24cm

Lisez la note de cours sur Elasticity (JAMB)

Elasticity

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Question 20 Rapport

When two parallel wires carry currents in opposite directions, the force on either wire is

away from the other wire

zero, because the currents cancel each other

twice as much as when the currents are in the same direction

towards the other wire

Newton’s Laws Of Motion

Equilibrium Of Forces

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Question 21 Rapport

In which of the following are the substance arranged in descending order of their thermal conductivities?

copper, steel, glass

steel, copper, glass

steel, glass, copper

copper, glass, steel

Heat Transfer

Fluid At Rest

Gravitational Field

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Question 22 Rapport

A 50kg block is dropped from a point 10cm above as shown in the fig above. if the force constant of the spring is 4.0 x 104Nm-1, find the maximum compression of the spring [g = 10ms-2]

1.25m

0.50m

0.25m

0.05m

Equilibrium Of Forces

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Question 23 Rapport

A radioactive sample initially contains N atoms. After three half-lives the number of atoms that have disintegrated is

N

8

3N

8

5N

8

7N

8

Détails de la réponse

N

\to

\frac{N}{2}

\to

\frac{N}{4}

\to

\frac{N}{8}

Lisez la note de cours sur Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 24 Rapport

he lowest note emitted by a stretched string has a frequency of 40Hz. How many overtones are there between 40Hz and 150Hz?

1

2

3

4

Détails de la réponse

In stretched strings the overtones are in odd multiple of Fo.

F1 = 3Fo

= 3 x 40 = 120Hz

F2 = 5Fo

= 5 x 40

= 200Hz

Lisez la note de cours sur Propagation Of Sound Waves (JAMB)

Propagation Of Sound Waves

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Question 25 Rapport

What type of reaction is represented by the following scheme?

\[ {}^{2}_{1}X + {}^{2}_{1}Y + {}^{3}_{2}Z + {}^{1}_{0}n + \text{energy} \]

Fusion reaction

Fission reaction

Chain reaction

Radioactive decay

Elementary Modern Physics

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Question 26 Rapport

A jet engine develops a thrust of 270Ns when the velocity of the exhaust gases relative to the engine is 300ms-1. What is the mass of the material ejected per second?

81.00kg

9.00kg

0.90kg

0.09kg

Détails de la réponse

Thrust = force x time

thrust = $\frac{m (v - u)}{t}$ x $\frac{t}{1}$

270 = m(300 - 0)

m = 0.90kg

Lisez la note de cours sur Measurements And Units (JAMB)

Measurements And Units

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Question 27 Rapport

A ray of light is incident at an angle of 30o on one top surface of a parallel-sided glass block of refractive index 1.5. The ray finally emerges from the lower surface. What is the angular deviation of the emergent ray?

60o

39o

28o

0o

Reflection Of Light At Plane And Curved Surfaces

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Question 28 Rapport

Which of the following instruments has a pure tone?

guitar

vibrating strings

tuning fork

siren

Sound Waves

Work, Energy And Power

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Question 29 Rapport

If a beaker is filled with water it is observed that the surface of the water is not horizontal at the glass-water interface. This behavior is due to

friction

viscosity

surface tension

evaporation

Friction

Temperature And Its Measurement

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Question 30 Rapport

The vacuum in a thermos flask helps to reduce heat transfer by?

convection and radiation

convection and conduction

conduction and radiation

radiation only

Heat Transfer

Temperature And Its Measurement

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Question 31 Rapport

Which of the following phenomena explains the fact that a house whose roof is coated with white paint will be cooler in the hot season than one coated with black paint ?

conduction

convection

refraction

reflection

Pressure

Simple A.C Circuits

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Question 32 Rapport

If the angle of declination in a place is 10oE, calculate the true geographic bearing if the compass reads N40oE

N50oE

N40oE

N30oE

N25oE

Speed And Velocity

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Question 33 Rapport

22,000J of heat is required to raise the temperature of 1.5kg of paraffin from 20oC to 30oC. Calculate the specific heat capacity of paraffin.

1466Jkg-1oC-1

2933Jkg-1oC-1

4400Jkg-1oC-1

5866Jkg-1oC-1

Détails de la réponse

22,000 = 1.5 x c x (30 - 20)

c = 1466Jkg-1oC-1

Lisez la note de cours sur Heat Energy (WAEC)

Heat Energy

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Question 34 Rapport

When the length I of a piece of wire under constant tension is varied, the relationship of the frequency of the vibration $ \alpha $/ is

f

α

/

f

α \frac{1}{I^{2}}

f

α \sqrt{I}

f

1

Détails de la réponse

F =

\frac{1}{2 L} \sqrt{\frac{T}{m}}

Lisez la note de cours sur Newton’s Laws Of Motion (WAEC)

Lisez la note de cours sur Equilibrium Of Forces (WAEC)

Newton’s Laws Of Motion

Equilibrium Of Forces

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Question 35 Rapport

The length of a side of a metallic cube at 20oC is 5.0cm. Given that the linear expansivity of the metal is 4.0 x 10-5k-1, find the volume of the cube at 120oC .

126.50cm3

126.25cm3

126.00cm3

125.00cm3

Détails de la réponse

Y =

\frac{V_{2} - V_{1}}{V_{1} \times θ}

3 x 4 x 10-5 = $\frac{V_{2} - 125}{125 \times (120 - 20)}$

V2 = 126.50cm3

Lisez la note de cours sur Temperature And Its Measurement (JAMB)

Temperature And Its Measurement

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Question 36 Rapport

A body rolls down a slope from a height of 100m. its velocity at the foot of the slope is 20ms-1. What percentage of its initial potential energy is converted into kinetic energy? [g = 10ms-1]

40%

35%

20%

15%

Détails de la réponse

P.E = mgh = 1000m joules

K.E = $\frac{1}{2}$ mv2 = 200m joules

%converted = $\frac{200 m}{1000 m}$ x 100

= 20%

Lisez la note de cours sur Measurements And Units (JAMB)

Measurements And Units

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Question 37 Rapport

Which of the following statements is TRUE of photoelectric effect?

it cannot occur in liquids

the energy of the emitted electrons is independent of the work function of the surface

the energy of the emitted electron depends on the wavelength of the incident light

the greater the intensity of the incuident light, the greater the incident of the emitted electron

Structure Of The Atom (Nigeria Only)

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Question 38 Rapport

A cube of side 10cm and mass 0.5kg floats in a liquid with only $ \frac{1}{5} $ of its height above the liquid surface. What is the relative density of the liquid?

0.125cm-1

0.250gcm-1

0.625cm-1

2.500cm-1

Détails de la réponse

Height below liquid = 1 -

\frac{1}{5}

=

\frac{4}{5}

volume of cube = 103cm3

volume of liquid displaced = $\frac{4}{5}$ x 1000

= 800cm3

density of liquid displaced;

= $\frac{500}{800}$

= 0.625cm-1

Lisez la note de cours sur Light Energy (JAMB)

Lisez la note de cours sur Simple Harmonic Motion (WAEC)

Lisez la note de cours sur Quantity Of Heat (JAMB)

Light Energy

Simple Harmonic Motion

Quantity Of Heat

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Question 39 Rapport

In the figure above, M and N are insulated metal spheres in contact. A negatively charged ebonite rod P is I brought near M. When M and N are Separated and the rod is taken away, which of the following statements is correct

both M and N have acquired negative charges

both M and N have acquired positive charges

M has acquired negative charge and N positive charge

N has acquired negative charge and M positive charge

Electrostatics

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Question 40 Rapport

A boat at anchor is rocked by waves whose crest are 100m apart and whose velocity is 25ms-1. At what interval does the wave crest reach the boat?

2500.00s

75.00s

4.00s

0.25s

Détails de la réponse

Distance between the boat and crest = 100m

time = $\frac{100}{25}$

= 4sec

Voir la réponse

Question 41 Rapport

A constant force of 40N acting on a body initially at rest gives an acceleration of 0.1ms-2 for 4s. Calculate the work done by the force

8J

10J

32J

160J

Détails de la réponse

X = ut +

\frac{1}{2}

at2

= (0 x 4) + ( $\frac{1}{2}$ x 0.1 x 4 x 4)

= 0.8m

workdone = force x distance

= 40 x 0.8

= 32J

Lisez la note de cours sur Work, Energy And Power (WAEC)

Lisez la note de cours sur Equilibrium Of Forces (WAEC)

Work, Energy And Power

Equilibrium Of Forces

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Question 42 Rapport

The velocity time graph above describes the motion of a particle between two points P and Q. What is the distance between P and Q?

17.0m

18.0m

22.5m

30.0m

Motion

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Question 43 Rapport

Isotopes are nuclei which have

the same number of nuetrons and electrons

equal number of electrons and protons

the same atomic number but different number of neutrons

the same number of total particles

Structure Of The Atom (Nigeria Only)

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Question 44 Rapport

The distance between the fixed points of a centigrade thermometer is 20cm. What is the temperature when the mercury level is 4.5cm above the lower mark?

22.5oC

29.0oC

90.0oC

100.0oC

Détails de la réponse

20cm .... 100oC

4.5cm .... $θ$

0cm ....0oC

$\frac{4.5 - 0}{20 - 0}$ = $\frac{0 - 0}{100 - 0}$