Waec Physics 1999 Past Questions and Answers

Question 46:

• WAEC 1999

The half-life of a radioactive substance is

A. Its average life time
B. One-half the value of its decay constant.
C. The length of time needed by the substance to decay completely
D. The length of time during which the activity of the substance reduces by 50%.

Question 47:

• WAEC 1999

The half-life of a radioactive element is 5 Calculate its decay constant

A. 0.113s^-1
B. 0.436 s^-1
C. 0.139 s^-1
D. 0.193 s^-1.

Question 48:

• WAEC 1999

A sheet of paper is placed in the path of the following radiations: I. Alpha particles II. Beta particles III. Gamma rays. Which of the radiations will pass through the sheet of paper?

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

Question 49:

• WAEC 1999

Which of the following are the essential parts of an atomic bomb?

A. Uranium and neutrons
B. Radium and polonium
C. Nitrogen and neutrons
D. Ranium and α - particles.

Question 50:

• WAEC 1999

Which of the following is not a safety precaution in a nuclear station?

A. Radioactive materials are stored in glass casings
B. Radioactive materials are handled with remote-controlled tongs
C. Technicians in nuclear stations wear radio-sensitive badges which are checked regularly.
D. Radioactive materials are kept in thick-walled lead containers