JAMB Physics 2007 past questions and answers

A glass plate 0.9 cm thick has a refractive index of 1.50. How long does it take for a pulse of light to pass through the plate? [c = 3.0 × 10⁸ ms⁻¹]

1. A.3.0 × 10⁻¹¹s
2. B.4.5 × 10⁻¹¹s
3. C.3.0 × 10⁻¹⁰s
4. D.4.5 × 10⁻¹³s

The fundamental frequency of a plucked wire under a tension of 400 N is 250 Hz. When the frequency is changed to 500 Hz at constant length, the tension is

1. A.40 N.
2. B.160 N.
3. C.400 N.
4. D.1600 N.

The production of pure spectrum could easily be achieved using a

1. A.triangular prism only.
2. B.triangular prism with two concave lenses.
3. C.triangular prism with two convex lenses.
4. D.glass prism with a pin.

The instrument used by designers to obtain different colour patterns is called

1. A.episcope.
2. B.periscope.
3. C.kaleidoscope.
4. D.sextant.

When an object is placed between the principal focus and the optical centre of a convex lens, it could be used as a

1. A.reflecting lens.
2. B.compound microscope.
3. C.projector.
4. D.simple microscope.

In a large telecommunications auditorium, perforated absorbent materials are used to line the ceiling so as to

1. A.reduce the reverberation of sound in the hall.
2. B.reduce the height of the ceiling from the floor.
3. C.increase the reverberation of sound in the hall.
4. D.increase the amount of echo in the hall.

The phenomenon of light bending round an obstacle is

1. A.reflection.
2. B.polarization.
3. C.refraction.
4. D.diffraction.

The energy E of a photon and its wavelength are related by Eλ=X. The numerical value of X is [h=6.63 × 10⁻³⁴ Js, c=3 × 10⁸ ms⁻¹]

1. A.1.99 × 10⁻²⁷.
2. B.6.60 × 10⁻²⁶.
3. C.1.99 × 10⁻²⁵.
4. D.6.60 × 10⁻²⁸.

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

1. A.1/16
2. B.1/8
3. C.1/4
4. D.1/32.

Silicon doped with aluminium and germanium doped with arsenic become

1. A.n- type semiconductors.
2. B.p- type semiconductors.
3. C.n- and p- types respectively.
4. D.p- and n- types respectively.

A photon of wavelength 6.0 × 10⁻⁷m behaves like a particle of a certain mass. The value of that mass is [h=6.63 × 10⁻³⁴ Js, c=3 × 10⁸ ms⁻¹]

1. A.1.1 × 10⁻³⁵ kg.
2. B.2.2 × 10⁻²⁷ kg.
3. C.3.5 × 10⁻³⁶ kg.
4. D.2.2 × 10⁻³⁵ kg.

During the nuclear reactions described by ²³⁵₉₂W → ²³⁵₉₃X → ²³¹₉₁Y, the particles emitted are respectively

1. A.β and β.
2. B.β and α.
3. C.α and β.
4. D.α and α.

The bond that forms a semiconductor is

1. A.ionic.
2. B.metallic.
3. C.covalent.
4. D.electrovalent.

The instrument that measures both a.c. and d.c. is

1. A.an inverter.
2. B.a current balance.
3. C.a moving coil ammeter.
4. D.a moving iron ammeter.

Lenz's law is a law of the conservation of

1. A.energy.
2. B.momentum.
3. C.electric current.
4. D.electric charge.

Three cells each of e.m.f. 1.5 V and internal resistance 2.5Ω are connected as shown in the diagram above. Find the net e.m.f. and the internal resistance.

1. A.4.5V, 7.50 Ω.
2. B.4.5V, 0.83 Ω.
3. C.1.5V, 7.50 Ω.
4. D.1.5V, 0.83 Ω.

A 120 V, 60 W lamp is to be operated on 220 V a.c. supply mains. Calculate the value of non-inductive resistance that would be required to ensure that the lamp is run on correct value.

1. A.500Ω.
2. B.300Ω.
3. C.200Ω.
4. D.100Ω.

In the diagram above, if the magnetic field points into the paper and the force on a current-carrying conductor points upwards, what is the direction of the current?

1. A.Downwards
2. B.Right
3. C.Left
4. D.Upwards

The instantaneous value of the induced e.m.f. as a function of time is ε=ε₀ sin ωt where ε₀ is the peak value of the e.m.f. The instantaneous value of the e.m.f., one quarter of the period, is

1. A.ε₀
2. B.ε₀/2
3. C.ε₀/4
4. D.0.

A conductor has a diagram of 1.00 mm and length 2.00 m. If the resistance of the material 0.1Ω, its resistivity is

1. A.3.93 × 10⁻⁸ Ωm.
2. B.3.93 × 10⁻⁶ Ωm.
3. C.2.55 × 10² Ωm.
4. D.2.55 × 10⁵ Ωm.

A charge 50 μC has an electric field strength of 360 NC⁻¹ at a certain point. The electric field strength due to another charge 120 μC kept at the same distance apart and in the same medium is

1. A.18 NC⁻¹
2. B.144 NC⁻¹
3. C.150 NC⁻¹
4. D.864 NC⁻¹

Two long parallel wires X and Y carry currents 3A and 5A respectively. If the force experienced per unit length by X is 5 × 10⁻⁵ N, the force per unit length experienced by wire Y is

1. A.5 × 10⁻⁴ N.
2. B.3 × 10⁻⁶ N.
3. C.3 × 10⁻⁵ N.
4. D.5 × 10⁻⁵ N.

From the diagram above, the inductive reactance and the resistance R are respectively

1. A.10Ω and 50Ω.
2. B.20Ω and 50Ω.
3. C.25Ω and 51Ω.
4. D.50Ω and 45Ω.

A 40 kW electric cable is used to transmit electricity through a resistor of resistance 2.0 Ω at 800 V. The power loss as internal energy is

1. A.5.0 × 10² W.
2. B.4.0 × 10³ W.
3. C.5.0 × 10³ W.
4. D.4.0 × 10² W.

If two charged plates are maintained at a potential difference of 3 kV, the work done in taking a charge of 600 μC across the field is

1. A.9.0 J.
2. B.0.8 J.
3. C.18.0 J.
4. D.1.8 J.

The ratio of the coefficient of linear expansion of two metals α₁/α₂ is 3:4. If, when heated through the same temperature change, the ratio of the increase in lengths of the two metals, e₁/e₂ is 1:2, the ratio of the original lengths is l₁/l₂

1. A.2/3
2. B.8/3
3. C.3/8
4. D.3/2

I. Mass II. Density III. Temperature IV. Nature of substance.
Which of the above affect diffusion?

1. A.I, II and IV only
2. B.II, III and IV only
3. C.I, II, III and IV.
4. D.I and II only.

A string of length 4 m is extended by 0.02 m when a load of 0.4 kg is suspended at its end. What will be the length of the string when the applied force is 15 N? [g=10ms⁻²]

1. A.5.05 m
2. B.6.08 m
3. C.4.05 m
4. D.4.08 m

I. Use a liquid with a high melting point.
II. Use a liquid of high volume expansivity.
III. Use a capillary tube of large diameter.
Which of the above best describes how the sensitivity of a liquid-in-glass thermometer can be enhanced?

1. A.II only
2. B.II and III only
3. C.I only
4. D.I and III only

The blade of a hoe feels colder to touch in the morning than the wooden handle because the

1. A.handle contains stored energy in form of heat
2. B.blade is placed at a lower temperature than the handle
3. C.handle is a better conductor of heat than the blade
4. D.blade is a better conductor of heat than the handle

A piece of iron weighs 250 N in air and 200 N in a liquid of density 1000 kgm⁻³. The volume of the iron is [g=10ms⁻²]

1. A.2.0 × 10⁻³ m³.
2. B.2.5 × 10⁻³ m³.
3. C.4.5 × 10⁻³ m³.
4. D.5.0 × 10⁻³ m³.

I. Increase the melting point of the liquid.
II. Increase the boiling point of the liquid.
III. Decrease the melting point of the liquid.
IV. Decrease the boiling point of the liquid.
Which of the statements above about the effects of increase in pressure in a liquid are correct?

1. A.II and III only
2. B.I and II only
3. C.III and IV only
4. D.I and III only

A blacksmith heated a metal whose cubic expansivity is 6.3 × 10⁻⁶ K⁻¹. The real expansivity is

1. A.6.3 × 10⁻⁶ K⁻¹.
2. B.4.2 × 10⁻⁶ K⁻¹.
3. C.2.1 × 10⁻⁶ K⁻¹.
4. D.2.0 × 10⁻⁶ K⁻¹.

The differences observed in solids, liquids and gases may be accounted for by

1. A.their relative masses.
2. B.their melting points.
3. C.the different molecules in each of them.
4. D.the spacing and forces acting between the molecules.

A reservoir 500 m deep is filled with a fluid of density 850 kgm⁻³. If the atmospheric pressure is 1.05 × 10⁵ Nm⁻², the pressure at the bottom of the reservoir is [g=10ms⁻²]

1. A.4.36 × 10⁶ Nm⁻².
2. B.4.25 × 10⁶ Nm⁻².
3. C.4.72 × 10⁶ Nm⁻².
4. D.4.28 × 10⁶ Nm⁻².

A clinical thermometer is different from other mercury in glass thermometers owing to

1. A.its long stem.
2. B.the constriction on its stem.
3. C.its wide range of temperatures.
4. D.the grade of mercury used in it.

2 kg of water is heated with a heating coil which draws 3.5 A from a 200 V mains for 2 minutes. What is the increase in temperature of the water? [Specific heat capacity of water = 4200 Jkg⁻¹ K⁻¹]

1. A.25°C
2. B.15°C
3. C.10°C
4. D.30°C

A boy drags a bag of rice along a smooth horizontal floor with a force of 2 N applied at an angle of 60° to the floor. The work done after a distance of 3 m is

1. A.6 J.
2. B.5 J.
3. C.4 J.
4. D.3 J.

The figure above shows 4 forces 3 N, 10N, 3√3 N and 6 N acting on a particle P. The resultant of the four forces is

1. A.10√3 N.
2. B.10 N.
3. C.5√3 N.
4. D.5 N.

Two spheres of masses 5.0 kg and 10.0 kg are 0.3 m apart. Calculate the force of attraction between them. [G=6.67 × 10⁻¹¹ Nm² kg⁻²]

1. A.3.71 × 10⁻⁸ N.
2. B.3.57 × 10⁻² N.
3. C.4.00 × 10² N.
4. D.3.50 × 10⁻¹⁰ N.

A car of mass 1500 kg goes round a circular curve of radius 50 m at a speed of 40 ms⁻¹. The magnitude of the centripetal force on the car is

1. A.1.2 × 10³ N.
2. B.1.2 × 10³ N.
3. C.4.8 × 10³ N.
4. D.4.8 × 10⁴ N.

The unit of moment of a couple can be expressed in

1. A.Nm
2. B.Nm⁻¹
3. C.Nm².
4. D.Nm⁻².

A machine has a velocity ratio of 4. If it requires 800 N to overcome a load of 1600 N, what is the efficiency of the machine?

1. A.2%
2. B.40%
3. C.50%
4. D.60%

In the diagram above, a rod 50 cm long of uniform cross-section is suspended horizontally on a fulcrum, F, by the action of two forces. What is the weight of the rod?

1. A.120N
2. B.200 N
3. C.40 N
4. D.80 N.

A gramophone record takes 5s to reach its constant angular velocity of 4π rads⁻¹ from rest. Find its constant angular acceleration.

1. A.20.0π rads⁻².
2. B.1.3π rads⁻².
3. C.0.8π rads⁻².
4. D.0.4π rads⁻².

A particle of weight 120 N is placed on a plane inclined at an angle 30° to the horizontal. If the plane has an efficiency of 60%, what is the force required to push the weight uniformly up the plane?

1. A.210 N
2. B.175 N
3. C.100 N
4. D.50 N.

From the diagram above, the bob of the pendulum has the fastest speed at

1. A.W.
2. B.Z.
3. C.Y.
4. D.X.