Physics 1988 Waec Past Questions and Answers

Question 51 :

• WAEC 1988

An electron of charge 1.6 x 10¹⁹C is accelerated in vacuum from rest at zero volt towards a plate of 40KV. Calculate the kinetic energy of the electron.

A. 4 x 10 ²⁵J
B. 4 x 10²¹ J
C. 6.4 x 10²⁰ J
D. 6.4 x 10^-15 J
E. 2.5 x 10²⁰ J

Question 52 :

• WAEC 1988

Which of the following is not an electromagnetic radiation?

A. X-ray
B. Radio waves
C. Sunlight
D. Sound waves
E. Infra-red radiation

Question 53 :

• WAEC 1988

Two radioactive elements A and B have half-lives of 100 and 50 years respectively. Samples of A and B initially contain equal amounts/number of atoms. What is the ratio of the number of the remaining atoms of A to that of B after 200 years?

A. 4 : 1
B. 2 : 1
C. 1 : 1
D. 1 : 2
E. 1 : 4

Question 54 :

• WAEC 1988

During the same interval, it is observed that a train travels the same distance as does a lorry. The two vehicles therefore have the same

A. Uniform accelation
B. Instateneous velocity
C. Initial velocity
D. Average speed
E. Average velocity

Question 55 :

• WAEC 1988

(a) Explain with the aid of a diagram what is meant by the moment of a force about a point.
(b) State the conditions of equilibrium for a number of coplanar parallel forces.
A metre rule is found to balance at the 48cm mark. When a body of mass 60g is suspended at the 6cm mark, the balance point is found to be at the 30cm mark. Calculate:
(i) the mass of the metre rule; (ii) the distance of the balance point from the zero end, if the body were moved to the 13cm mark.
(c) Show that the efficiency E, the force ratio M.A and the velocity ratio V.R of a machine are related by the equation \(E = \frac{M.A}{V.R} \times 100%\)
The efficiency of a machine is 80%. Determine the work done by a person using this machine to raise a load of 200kg through a vertical distance of 3.0m.
[Take g = 10ms\(^{-2}\)]