Waec Physics Past Questions For Year 1992
Question 56
An electric string of length l is elastically stretched through a length e by a force F. The area of cross- section of the string is A and its Young’s modulus is E. Which of the following expressions is correct?
- A. F = EA/eI
- B. F = EAI/e
- C. F = EAe/l
- D. F = EAe
Question 57
The process by which a metal, heated to high temperature, gives off electrons from its surface is known as
- A. photoelectric emission
- B. thermionic emission
- C. radioactive emission
- D. Held emission
- E. secondary emission
Question 58
A sheet of paper is placed in the path of a beam of radiations from a radioactive source. Which of the following radiations will pass through the paper?I. Alpha rays II. Beta rays III. Gamma rays
- A. I only
- B. II only
- C. III only
- D. II and III only
- E. I, II and III
Question 59
When the nucleus of a uranium atom is split into two fragments of nearly equal mass the sum of the masses of the fragments is less than the mass of the original nucleus. This difference is a measure of the
- A. experimental error in calculating the separate masses
- B. change of momentum of each fragment
- C. potential energy lost
- D. nuclear energy released
- E. kinetic energy lost
