Jamb Physics 2000 Past Questions and Answers

Question 26:

• JAMB 2000

in a pure semiconductor, the number of electrons in the conduction band is

A. Less than the number of holes in the valence band
B. Equal to the number of holes in the valence band
C. Greater than the number of holes in the valence band
D. Twice the number of holes in the valence band

Question 27:

• JAMB 2000

In a thermonuclear reaction, the total initial mass is 5.02 x \(10^{-{2}{7}}\)kg and the total final mass is 5.01 x \(10^{-{2}{7}}\)kg. The energy released in the process is
[c = 3.0 x \(10^8\) ms-1]

A. 9.0 x 10^-13J
B. 9.0 x 10^-12J
C. 9.0 x 10^-11J
D. 9.0 x 10^-10J

Question 28:

• JAMB 2000

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 29:

• JAMB 2000

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

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

Question 30:

• JAMB 2000

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