Physics Past Questions and Answers

Both \(\gamma\)-rays and X-rays i. can be produced by thermionic emission ii. have low frequencies iii. have short wavelengths. Which of the statements above is/are correct?

A I only
B Ii only
C Iii only
D I and iii only

Question 1252:

When a radioactive substance undergoes a beta decay, its

A Mass number decreases by 1
B Atomic number decreases by 1
C Mass number increases by 1
D Atomic number increases by 1

Question 1253:

Nuclear fission is preffered to nuclear fusion in the generation of energy because

A Very high temperature are required for fusion
B The raw materials for fusion are easily obtained
C Energy obtained from fusion is relatively small
D The by-products of fusion is very dangerous

Question 1254:

Control in nuclear reactors is effected with boron rods because rhe rods have the ability to

A Absorb electrons
B Absorb neutron
C Accelerate electrons
D Slow down neutrons

Question 1255:

A radioactive element has a decay constant of 0.077s^-1. Calculate its half-life

A 13.0s
B 9.0s
C 5.1s
D 0.5s