2019 JAMB Physics Past Questions CBT

Electrons were discovered by

Which of the following is/are the limitations to Rutherford’s atomic models?

I. It is applicable when energy is radiated as electrons are revolving
II. It is applicable when energy is radiated in a continuous made
III. It is applicable to an atom with only one electron in the other shell.

In a slide wire bridge, the balance is obtained at a point 25 cm from one end of a wire 1m long. The resistance to be tested is connected to that end and a standard resistance of 3.6 Ω is connected to the other end of the wire. Determine the value of the unknown resistance

Which of the following equation is the correct definition of the reactance of an inductor L?

Reactance =

Ripple in a power supply unit is caused by

When the temperature of a liquid is increased, its surface tension

The distance between an object and its real image in a convex lens is 40 cm. If the magnification of the image is 3, calculate the focal length of the lens

Lamps in domestic lightings are usually in

A ray of light passes through the center of curvature of a concave mirror and strikes the mirror. At what angle is the ray reflected?

The pin-hole camera produces a less sharply defined image when the

The value of T in the figure above is

A straight wire 15 cm long, carrying a current of 6.0 A is in a uniform field of 0.40 T. What is the force on the wire when it is at the right angle to the field?

The pitch of a screw jack is 0.45 cm and the arm is 60 cm long. If the efficiency of the Jack is \(\frac{75}{\pi}\scriptsize \%\), calculate the mechanical advantage.

When the downward current flows in a straight vertical conductor, the direction of its magnetic field at a point due north of the wire is

Aluminium is sometimes used as the leaf of an electroscope because it

The diagram above represents the stress-strain graph of a landed wire. Which of these statements is correct?

A supply of 400 V is connected across capacitors of 3 μF and 6 μF in series. Calculate the charge.

A vibrator causes water ripples to travel across the surface of a tank. The wave travels 50 cm in 2 s and the distance between successive crests is 5 cm. Calculate the frequency of the vibrator.

A thermocouple thermometer is connected to a millivoltmeter which can read up to 10 mV. When one junction is in ice at 0°C and the other is steam at 100°C, the millivoltmeter reads 4 mV. What is the maximum temperature that this arrangement can measure?

An alternating current can induce voltage because it has

The limiting frictional force between two surfaces depends on

I. the normal reaction between the surfaces
II. the area of the surface in contact
III. the relative velocity between the surfaces
IV. the nature of the surfaces

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because

The statement ‘Heat lost by the hot body equals that gained by the cold one’ is assumed when determining specific heat capacity by the method of mixtures. Which of the following validates the assumption?

I. Lagging the Calorimeter
II. Ensuring that only S.I units are used
III. Weighing the calorimeter, the lid and the stirrer.

Which of the following graphs is consistent with Charles’ law?

In the molecular explanation of conduction, heat is transferred by the

The conductivity of gases at low pressure can be termed as

I. hot cathode emission
II. thermo ionic emission
III. cold cathode emission
IV. field emission

Which of the following media allow the transmission of sound waves through them?

I. Air
II. Liquid
III. Solids

The earth’s gravitational field intensity at its surface is about _______

(G = 6.7 × 10^-11 Nm²/kg², mass of the earth is 6 × 10²⁴ kg, radius of the earth is 6.4 × 10⁶ m, g on the earth = 9.8 m/s²)

A train has an initial velocity of 44 m/s and an acceleration of -4 m/s². Calculate its velocity after 10 sec.

The following are parts of the eye
I. Retina
II. Pupil
III. Iris

The correct equivalents in the camera in the same order are

According to kinetic molecular model, in gases

A force of 6 N acts horizontally on a stationary mass of 2 kg for 4 s. The kinetic energy gained by the mass is _________

The momentum of a car moving at a constant speed in a circular track

A metal rod has a length of 100 cm at 200°C. At what temperature will its length be 99.4 cm if the linear expansivity of the material of the rod is 2 × 10^-5 °C^-1?

The lead-acid accumulator consists of

When water is boiling, it

A mixture of blue and red pigment, when illuminated by white light will appear

A siren having a ring of 200 holes makes 132 rev/min. A jet of air is directed on the set of holes. Calculate the frequency and wavelength in air of the note produced (take v = 350 m/s)

A man on a bench will exert the greatest pressure on the bench when he

Gases conduct electricity under

A body moves in SHM between two points 20 m on the straight line joining the points. If the angular speed of the body is 5  rad/s. Calculate its speed when it is 6 m from the center of the motion.

The diagram shows a uniform meter rule AB which balances horizontally at the 90 cm mark when a mass of 0.2 kg is suspended from B. Calculate the mass of the meter rule.

The equilibrium position of objects in any field corresponds to situation of

The height at which the atmosphere ceases to exist is about 80 km. If the atmospheric pressure on the ground level is 760 mmHg, the pressure at a height of 20 km above the ground level is
(ρm= 13.6 g/cm³, ρ = 0.00013 g/cm³)

A cone in unstable equilibrium has its potential energy

A mass of 0.5 kg is whirled in a vertical circle of radius 2m at a steady rate of 2 rev/s. Calculate the centripetal force

A body was slightly displaced from its equilibrium position. Which one of the following is a condition for its stable equilibrium

Which of the following readings cannot be determined with a meter rule?

When blue and green colours of light are mixed, the resultant colour is

If the time of flight is 96 seconds, calculate the horizontal range through the point of projection.