Physics 1990 Waec Past Questions and Answers

Question 51 :

• WAEC 1990

Which of the following reduce(s) the effect of the back e.m.f. generated in the primary coil of an induction coil? The capacitor in the circuit II. The make and break contact in the circuit III. The ratio of turns in the secondary to that in the primary

A. L only
B. II only
C. I and II only
D. II and III only
E. I, II and III.

Question 52 :

• WAEC 1990

Which of the following particles conduct electricity through salty water?

A. Atom
B. Molecules
C. Electrons
D. Neutrons
E. Ions

Question 53 :

• WAEC 1990

When the pressure of the gas in a discharge tube is gradually lowered. I. there is a violet glow in the tube II. the glow in the tube splits into bands which get further apart. III, the glow and the bands eventually disappear and there is a green fluorescence in the tube. IV. the tube breaks into pieces. Which of the following are correct?

A. I and II only
B. I and III only
C. I and IV only
D. I, II and III only
E. I, II III and IV

Question 54 :

• WAEC 1990

Which of the following statements about the atom is/are correct? I. Energy is needed to remove electrons from an atom II. Particles in the nucleus of an atom are bound together by strong forces. III. A large amount of energy is required to separate the particles in the nucleus of an atom. IV. When the nucleus of a uranium atom is split, the energy released accounts for the difference in the masses of the products and the parent nucleus

A. I only
B. I and II only
C. I and III only
D. II and IV only
E. I, II, III and IV

Question 55 :

• WAEC 1990

The nucleon number and the proton number of a neutral atom of an element are 238 and 92 respectively. What is the number of neutrons in the atom?

A. 330
B. 165
C. 146
D. 119
E. 73