Physics Past Questions and Answers

A gas would serve as an electrical conductor under

A Reduced pressure and high current
B Increased magnetic field
C Reduced pressure and reduced potential
D Exposure to visible light

Question 1022:

An electric generator with a power output of 3.0KW at a voltage of 1.5KV distributes power along cables of resistance 20.0â„¦. The power loss in the cables is

A 80.0W
B 40.0W
C 10.0W
D 0.1W

Question 1023:

If the frequency of an emitted x-ray is 1.6 x 10¹⁶Hz, the accelerating potential is?
[e = 1.6 x 10^-19C, h = 6.63 x 10^-34Js]

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

Question 1024:

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

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

Question 1025:

A certain radioactive source emits radiations that were found to be deflected by both magnetic and electric fields. The radiations are

A Beta rays
B Gamma rays
C X-rays
D Unltr-violet rays