Waec Physics 1993 Past Questions and Answers

Question 56:

• WAEC 1993

A radioactive substance has a half-life of 20 hours. What traction of the original radioactive nuclide will remain after 80 hours?

A. 1/32
B. 1/16
C. 1/8
D. ¼
E. 1/2

Question 57:

• WAEC 1993

Which of the following is used a nuclear reactor to slow down fast moving neutrons?

A. Carbondioxide gas
B. Liquid sodium metal
C. Concrete shield
D. Graphite rods
E. Boron rods

Question 58:

• WAEC 1993

According to the kinetic theory of gases the collision
of the molecules of a gas with the wall of the container
is mainly responsible for the l. temperature of the
gas ll. viscosity of the gas Ill. pressure of the gas
Which of the statements above is/are correct?

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

Question 59:

• WAEC 1993

Eight or - particles and size B - particles are emitted from an atom of ₉₂²³⁸U before it achieves stability. What is the nucleon number of the final product in the chain reaction?

A. 206
B. 234
C. 238
D. 240
E. 252

Question 60:

• WAEC 1993

When an atom is in the ground state, it is said to be

A. Grounded
B. Excited
C. Stable
D. Ionized
E. Radiating