JAMB Physics 1983 past questions

Which of the following is NOT a vector quantity

P1 P3 O O3 O2 P2 Fig. 1 Consider the three forces acting at O and in equilibrium as shown in Fig. 1. Which of the following equation is/are CORRECT? I. P1 cos 01 = P1 cos O2 II. P3 = P1 cos O1 + P2 cos O2 III. P1 sin O1 = P2 sin O2

Brick Cord Pull Fig. 2 A brick at rest on a horizontal table is pulled by a horizontal cord, as shown in Fig. 2. The force of friction on the brick

The force with which an object is attracted to the earth is called its

The refractive index of a liquid is 1.5. If the velocity of light in vacuum is 3.0 x 108m s-1, the velocity of light in the liquid is

If the relative density of a metal is 19, what will be the mass of 20cm3 of the metal when immersed in water?

Which of the following statements about liquid pressure is NOT correct? The pressure

Which of the following is NOT correct? I. The pitch of a sound note depends on the frequency of vibrations. II. The intensity of a sound note is proportional to the amplitude of vibrations. III. Beats are produces by two sources of sound because one wave is travelling faster than the other. IV. When two sources of sound of frequencies 500 Hz and 502 Hz are sounded together, a neat frequency of 2 Hz is observed. V. The first harmonic of a note has double the frequency of the fundamental note.

Which of the following statements about defects of vision is/ are CORRECT I. For a long sighted person, close objects appear blurred. II. For a sort sighted person, distant objects appear blurred. III. Short sight is corrected by using a pair of converging lenses.

The range of wavelengths of the visible spectrum is 400nm – 700nm. The wavelength of gamma rays is

If the pressure on 1000cm3 of an ideal gas is doubled while its Kelvin temperature is halved, then the new volume of the gas will become

Which of the following conditions are necessary and sufficient for total internal reflection to take place at the boundary between two optical media? I Light is passing from optically denser medium to optically less dense medium. II Light is passing from optically less dense medium to optically denser medium. III Angle of incidence is greater. IV Angle of incidence if lesser.

Which of the following arrangements in the sequence shown can be used to obtain a pure spectrum of white light?

10V I1 2Ù I2 [PAGE 4] 20V 2Ù I3 1Ù 20V I4 2Ù I5 1Ù Fig. 3. The diagrams in Fig.3 show three circuits. The internal resistances of the batteries are negligible. Which of the currents is the largest?

It is usual to transmit electric power at high voltage and low current. Which of the following are possible advantages of the method. I Heat losses are reduced because the currents are small. II Thin wires can be used because small currents are flowing. III The power can flow faster because the voltage is high.

The linear expansivity if brass is 2 x 10-1 0C-1. If the volume of a piece of brass is 100cm3 at 00C, what will be its volume at 1000C?

A 24V potential difference is applied across a parallel combination of four 6-ohm resistors. The currents in each resistor is

In the circuit shown in Fig. 4, T is a resistor whose resistance falls as temperature increases. L1 and L2 are lamps. Assuming the cell has negligible internal resistance, as the temperature of T increases

Which of the diagrams in Fig. 5 gives the correct resultant R of two vectors P and Q? P P R I II R Q Q P P R III IV R P R fig 5. V Q [PAGE 5]

The electrochemical equivalent of a metal is 0.126 x 10-6 kg/C. The mass of the metal that a current of 5A deposit from a suitable bath in 1 hour is

Ripples on water are similar to light waves in that they both

Of the following derived units, the one that is not a unit of power is

1,000 identical drops of oil of density 5000kg/m3 have a total mass of 5 x 10-4kg. One of the drops forms a thin film of area 0.5m2 on water. The thickness of the film is

The total length of a spring when a mass of 200g is hung from its end is 14cm, while its total length is 16cm when a mass of 30kg is hung from the same end. Calculate the unstretched length of the spring assuming Hooke’s law is obeyed.

Each of the diagrams in Fig. 6 represents two current carrying conductors situated close to each other. In which two diagrams are the forces between the two wires attractive? I II III IV V Fig .6

Which of the following statements is CORRECT? I The mass number is equal to the total number of protrons and electrons in an atom. II The atomic number is equal to the number of protrons in an atom [PAGE 6] III The number of electrons in an atom is equal to the total number of protons and neutrons in the nucleus.

If the normal atmospheric pressure in a laboratory supports a column of mercury 0.76m high and the relative density of mercury is 13.8, then the height of water column which atmospheric pressure will support in the same laboratory at the same time is

An electric current of 3A flowing through an electric heating element of resistance 20 embedded in 1,000g of an oil raises the temperature of the oil by 100C in 10 seconds, then the specific heat capacity of the oil is

The difference of potential between the terminals of a cell is 2.2 volts. When a 4 ohm resistor is connected across the terminals of this cell, the potential difference is 2 volts. What is the internal resistance of the cell?

Q I P R Fig. 7 In Fig. 7 above, QR is a vertical conductor and the current I flows from R to Q. P is a point on the horizontal plane and it to the South of the wire. The direction of the magnetic filed at P due to the current is

Which of the following best describes the energy changes which take place when a steam engine drives a generator which lights a lamp?

Which of the following statements clearly describe the behaviour of the fire alarm shown in Fig. 8 below given that the linear expansivities of copper and steel are 2.0 x 10-5/0C and 1.2 x 10-5/0C respectively? Electric bell Copper P Steel Q Fig. 8. [PAGE 7] I The bimetallic strip will not be able to close the circuit when there is fire II The bimetallic strip will close the circuit when there is fire III If the copper and steel are interchanged, the circuit will close when there is fire.

Four equal resistors R1, R2, R3 and R4 are connected in series as shown in Fig 9 below. V1, V2 and V3 are voltmeters connected as indicated. Which of the following relations is CORRECT?

Which of the following may be used to determine relative humidity in a physics laboratory? I Manometer II Wet-and-dry bulb hygrometer III Hair hygrometer IV A hydrometer

PQ is a thin rod on a horizontal table, RS is a plane mirror inclined at 450C to the horizontal as shown in Fig. 10 above. The image of PQ as seen in the mirror by the eye, T is

The speed of light in vacuum is 3.0 x 108m s-1. If the refractive index of a transparent liquid is 4/3 then the speed of light in the liquid is

If the force on a charge of 0.2 coulomb in an electric field is 4N, then the electric field intensity of the field is

The specific latent heat of vapourization of a substance is always

Longitudinal waves do not exhibit

Fig. 11 above shows an inverted U-tube with the open end, O of one limb below the level, W, of the water in a tank. In order that water should begin to flow from the tank it is necessary that