2020 JAMB Physics Past Questions CBT

A catapult used to hold a stone of mass 500 g is extended by 20 cm with an applied force F. If the stone leaves with a velocity of 40 ms^-1, The value of F is

A handbag containing some load weighing 162 N is carried by two students each holding the handle of the bag next to him. If each handle is pulled 60º to the vertical, find the force on each student’s arm.

I. The frictional force is independent of the area of the surface in contact.
II. The frictional force depends on the nature of the surface in contact.
III. The frictional force depends on the speed of sliding.
IV. The frictional force is directly proportional to the normal reaction.

Which combination of the above is true of sliding friction?

When a ship sails from salt water into fresh water, the fraction of its volume above the water surface will

A simple pendulum has a period of 17.0 s. When the length is shortened by 1.5 m, its period is 8.5 s. Calculate the original length of the pendulum.

At a fixed point below a liquid surface, the pressure downwards is P₁, and the pressure upwards is P₂. It can be deduced that

I. Its velocity is constant.
II. No work is done on the body.
III. It has constant acceleration directed away from the centre.
IV. The centripetal force is directed towards the centre.

Which combination of the above is true of a body moving with constant speed in a circular track?

The velocity v of a particle in a time t is given by the equation v = 10 + 2t².

Find the instantaneous acceleration after 5 seconds.

If the force and the velocity on a system are each reduced simultaneously by half, the power of the system is

The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150 N with the machine?

A rope is being used to pull a mass of 10 kg vertically upward. Determine the tension in the rope if, starting from rest, the mass acquires a velocity of 4 ms^-1 in 8 s.
[g = 10 ms^-2]

A stream is flowing at 0.75 ms^-1 and a boat heading perpendicular for the stream landed at the opposite bank at an angle 30°. Calculate the velocity of the boat.

I. Coherence
II. Same frequency
III. Same wavelength
IV. Same intensity

Which of the conditions above are necessary to produce interference fringes?

An engineer intends to deviate a light ray from its path by 120º through reflection from a plane mirror. Calculate the angle of incidence.

The reading above is for three consecutive days from a wet and dry bulb hygrometer. It can be concluded that the relative humidity for the three days

Total internal reflection occurs when light moves from

One end of a long wire is fixed while a vibrator is attached to the other end. When the vibration is energized, the type of waves generated in the wire are

Sonometer wire is vibrating at frequency f_o. If the tension in the wire is doubled while the length and the mass per unit length are kept constant, the new frequency of vibration is

A boy observes a piece of stone at the bottom of a river 6.0 m deep. If he looks from the surface of the river, what is the apparent distance of the stone from him?

[Refractive index of water = \(\frac{4}{3}\)]

Which of the following will allow the flow of electrons?

The diagram above shows a maximum and minimum thermometer divided into three portions P, Q and R. Which of the following is true about the respective content of P, Q and R?

The main reason for making the cover of a vacuum flask airtight is to prevent heat loss by

A travelling wave moving from left to right has an amplitude of 0.15 m, a frequency of 550 Hz and a wavelength of 0.01 m. The equation describing the wave is

A transverse wave is applied to a string whose mass per unit length is 3 × 10^-2 kgm^-1. If the string is under tension of 12 N, the speed of propagation of the wave is

A quantity of water at 0ºC is heated to about 30ºC At each degree rise in temperature, its density will

A thin wire with heavy weights attached to both ends is hung over a block of ice resting on two supports. If the wire cuts through the ice block while the block remains solid behind the wire, the process is called

A cell of internal resistance 0.01 Ω can be measured accurately using the

An electron of charge 1.6 × 10^-19 C and mass 9.1 × 10^-31 kg is accelerated between two metal plates with a velocity of 4 × 10⁷  ms^-1; the potential difference between the plates is

In the diagram above, a beam of white light travels from a rare to a dense medium. What colours of light do the rays a, b and c respectively represent?

The diagram above shows two capacitors P and Q of capacitances 5 µF and 10 µF. Find the charges stored in P and Q, respectively

What optical instrument can be constructed with converging lenses of focal lengths 50 cm and 5 cm?

If a charged ion goes through combined electric and magnetic fields, the resultant emergent velocity of ion is

In the diagram above, the values of V₁ and V₂ are respectively

A projection lantern is used to give the image of a slide on a screen. If the image is 24 times as large as the slide and the screen is 72.0 m from the projecting lens, what is the position of the slide from the lens?

A radio is operated by eight cells, each of e.m.f. 2.0 V connected in series, if two of the cells are wrongly connected, the net e.m.f. of the radio is

A 2 H inductor has negligible resistance and is connected to a 50/π Hz a.c supply. The reactance of inductor is

If the fraction of the atoms of a radioactive material left after 120 years is 1/64, what is the half-life of the material?

A certain radioactive source emits radiations that were found to be deflected by both magnetic and electric fields. The radiations are

In a pure semiconductor, the number of electrons in the conduction band is

A cell of internal resistance 1 Ω supplies current to an external resistor of 3 Ω. The efficiency of the cell is