Elementary Modern Physics - Jamb Physics Past Questions and Answers

Question 181:

• JAMB 2020

A substance has half of 3 min. After 6 min, the count rate was observed to be 400. What was its count rate at zero time?

A. 1600
B. 1200
C. 200
D. 2400

Question 182:

• JAMB 2021

If the fraction of the atoms of a radioactive material left after 120 years is 1/64, what is the half-life of the material?

A. 24 years
B. 20 years
C. 10 years
D. 2 years

Question 183:

• JAMB 2021

A certain radioactive source emits radiation that was found to be deflected by both magnetic and electric fields. The radiation is?

A. Beta rays
B. Gamma rays
C. X-rays
D. Ultra-violet rays

Question 184:

• JAMB 2021

If the frequency of an emitted x-ray is 1.6 x 10\(^{16}\)Hz, the accelerating potential is?

[e = 1.6 x 10\(^{-19}\)J, h = 6.63 x 10-\(^{34}\)Js]

A. 6630.0V
B. 663.0V
C. 66.3V
D. 6.6V