WAEC SSCE - Physics - 2020 (Objective)

The length of an iron bar is 100cm at 20°C. At what temperature will its length increase by 0.01%? [Linear expansivity of iron = 1.2 x 10\(^{-5}\)°C]

 A 60kg man stands on a weighing balance in an elevator. If the elevator accelerates upwards at 5ms\(^{-2}\), determine the reading of the scale. [g = 10ms\(^{-2}\)]
 

A moving-coil galvanometer which gives a full-scale on deflection with 0.005A is converted to a voltmeter reading up to 5V using an external resistance of 975\(\Omega\). What is the resistance of the metre?

The depolarising agent in a Leclanche cell is?

An electrical device has 50 turns in its primary coil  and 20 turns in the secondary coil. The device can be a\an?

Which of the following statement about viscosity is not true? it

The volume of a fixed mass of a gas varies inversely as the pressure on it provided the temperature is constant. This statement is

 In the hydraulic press, the force F applied is related to the diameter d of the cylinder by 
 

 Water waves have a wavelength of 3.6cm and speed of 18cms\(^{-1 }\) in deep water. If the waves enter shallow water with wavelength of 2.0cm, calculate the speed of the waves in the shallow water.

 A ray of light travels obliquely from a less dense medium to a denser medium. Which of the following statements is true about the light?
 

A motorcycle starting from rest is uniformly accelerated such that its velocity in 10s is 72kmhr\(^{-1}\). What is its acceleration?

 What factors determine the frequency of a note emitted by a vibrating string?

Which of the following waves requires a material medium for its propagation?

The velocity of sound in air at 15°C is 35400ms\(^{-1}\). Calculate the velocity at 47\(^o\)C

 In an electric circuit, an inductor of inductance 0.5 H and resistance 50\(\Omega\) is connected to an alternating current source of frequency 60 Hz. Calculate the impedance of the circuit.

Which of the following statements about photoelectrons is correct?

The average distance moved by a molecule between collisions is called

The quantity of motion of a body is its

 In photoelectric effect, the number of electrode emitted per second from a metallic surface is proportional to the

Which of the current-voltage characteristics shown below is that exhibited an ohmic conductor? 

The earpiece of a telephone handset converts energy from

A parallel plate capacitor is charged and the charging battery is subsequently disconnected. lf the plates of the capacitor are moved farther apart by means of insulating handles, the

 A 500N box rests on a horizontal floor. A constant horizontal force is exerted on the box so that it moves through 8m. If the coefficient of kinetic  friction between the floor and the box is 0.22, calculate the workdone on the box
 

The sketched graph above illustrates the heating curve of a 0.02kg of water. Determine the approximate value of the specific latent heat of vapourization of water
 

The material used to slow down the neutrons in a nuclear reactor is 
 

An electron of mass m and charge e moves in a circular path in a magnetic field of flux density B. How long does it take to complete one orbit? 

How would the capacitance of a parallel plate capacitor be affected if the distance of separation of its plates is decreased? It will

The diagram illustrates a ball of mass m sliding down a plank inclined at an angle of 0 to the horizontal. The kinetic friction between the ball and the plank is F and acceleration of free fall is g. The normal force on the ball is?

A diver steps off a diving platform that is 10m above the water. If there is no air resistance during the fall, there will be a decrease in the diver's

Which of the following statements about the process of melting of a solid are true? The temperature of the solid will 

I. remain steady until melting starts.

ll. keep rising until melting starts,

Ill remain steady as melting proceeds. 

V, keep rising as melting proceeds.

Which of the following statements about the motion of a simple pendulum is true?

In collision between two objects, kinetic energy is conserved only if

The magnitude of the force experienced by a charge of 1.6 x 10\(^{-8}\)C in a uniform electric field of intensity 5 x 105NC\(^{-1}\)  is

 Which of the following actions would increase the electric force between two positively charged particles?
 

The diagram above illustrates a beam of parallel rays from a distant object O, incident on one side of the total reflecting prism. Which diagram does not represent the correct path of the beam when it emerges from the prism?

A luminous object is one that

An image formed on a screen is always?

An a.c. generator can be converted to a d.c. electric motor by replacing the

The vacuum between the double walls of a thermos flask reduces heat loss through

Which of the following machines does not apply the lever principle?

Two identical cups containing the same volume of water at 45°C and 5°C, are left in a room at 25°C. Which of the following graphs correctly illustrates the variation of temperature with time?

Which of the following statements explain why hot soapy water is more effective in cleaning oil-stained dishes?

The temperature of an object is raised by 120°C. The resulting increase in its absolute temperature is
 

Which of the following units is not fundamental?

A beam consisting of \(\alpha\)-particles. \(\beta\)-particles and \(\gamma\)-rays pass through a magnetic field at right angles to the direction of the field. Which of the following observations would be made about the \(\alpha\)-particles, \(\beta\)-particles, and \(\gamma\)-rays respectively?

When two cells of negligible internal resistances and equal e.m.f. denoted by E\(_1\) and E\(_2\) are connected in parallel, combined e.m.f. E is given by
 

Which of the following statements correctly explains why a total solar eclipse would be seen by people on only a small portion of the earth's surface? The
 

The diagram above illustrates a ball of mass m sliding down a plank inclined at an angle of 0 to the horizontal. The kinetic friction between the ball and the plank is F and the acceleration of free fall is g. The net force on the ball along the plank is?

An electron of mass 9.1x 10\(^{31}\) kg is travelling at a speed of 2.0 x 10\(^6\)ms\(^{-1}\). Calculate the associate wavelength of the electron. [h = 6.6. x 10\(^{34}\) Js]

A ray of light traveling from glass into ethyl alcohol is incident at the boundary at an angle of incidence 30\(^o\). Calculate the angle of refraction.

[Refractive index of glass =1.5; refractive index of ethyl alcohol = 1.36]