JAMB Physics 1991 past questions

An object moves with uniform speed round a circle. Its acceleration has

T T1 10kg Find the tensionT1 in the diagram above if the system is in equilibrium.

F(N) 12 - 6 - 0 12 24 A body is under the action of a force F such that the force – displacement graph of the body is semicircular as shown above. The work done on the body by the force in moving through 24 metres is

A 20kg mass is to be pulled up a slope inclined at 300 to the horizontal. If the efficiency of the plane is 75%, the force required to pull the load up the plane is

The spiral spring of a spring balance is 25.0cm long when 5N hangs on it and 30.0cm long, when the weight is 10N. What is the length of the spring if the weight is 3N assuming Hooke’s Law is obeyed?

The mass of a stone is 15.0g when completely immersed in water and 10.0g when completely immersed in a liquid of relative density 2.0. The mass of the stone in air is

In which of the following is surface tension important?

What is the difference in the amount of heat given out by 4kg of steam and 4kg of water when both are cooled from 1000C to 800C? [The specific latent heat of steam is 2,260,000J kg1, specific heat capacity of water is 4200J kg-1 K-1]

How long does it take a 750-W heater to rise the temperature of 1kg to water from 200C to 500C? [Specific heat capacity of water = 4200J kg-1 K-1]

The saturated vapour pressure of a liquid increases as the

The absolute temperature of a perfect gas is proportional to the average

Which of the following is TRUE of light and sound waves?

The image in pin-hole camera is

When a plane mirror at which a ray is incident is rotated through an angle Q, the reflected ray will be rotated through

In a ray diagram for a thin converging lens, a ray that is not parallel to the optic axis but passes through the optic center will

Which of the following correctly describes the image of an object, 4cm from a diverging lens of focal length –12cm?

Two tuning forks of frequencies 256Hz and 260 Hz are sounded close to each other. What is the frequency of the beats produced?

When the bottom tip of a vibrating turning fork held in contact with a wooden box, a louder sound is heard. This phenomena is known as

Which of the following statements is CORRECT about the earth’s magnetic field?

The internal resistance of each of the cells E1 and E2 shown in the figure above is 2Ù. Calculate the total current in the circuit

The function of the system of granulated carbon mixed with manganese (IV) oxide in a Leclanche cell is to

Which of the following obeys Ohm’s Law?

The net capacitance in the circuit shown above is

In the above circuit, the fuse wire melts when

An equipment whose power is 1500W and resistance is 375 ohms would draw a current of

To convert an alternating current dynamo into a direct current dynamo, the

If a current carrying coil is mounted on a metal frame, the back e.m.f. induced in the coil causes

The electrochemical equivalent of platinum is 5.0 x 107 kg C-1. To plate-out 1.0kg of platinum, a current of 100A must be passed through n appropriate vessel for

Which of the following statements are TRUE of isotopes? I Isotopes of an element have the same chemical properties because they have the same number of electrons. II Isotopes of elements are normally separated using physical properties III Isotopes of an element have the same number of protons in the nuclei.

4g of a radioactive material of half-life 10 days is spilled on a laboratory floor. How long would it take to disintegrate 3.5g of the material?

In a nuclear fusion process, four protons each of mass Mp were fused to produce a nucleus X of mass Mx. Which of the following equations is CORRECT?

Which of the following are TRUE for á-decay I. Mass number decreases by four II Atomic number decreases by two III Mass number does not change.