Introductory Electronics - Jamb Physics Past Questions and Answers

Question 6:

• JAMB 2003

The major difference between a pure semiconductor and a pure metal is that

A. Metals are harder than semiconductor
B. While resistance of metals decrease with temperature , the reverse is the case for semiconductor
C. The resistance of metals increases with temperature, while for semiconductors, it is the reverse
D. Metals have forbidden gaps while semiconductors have not

Question 7:

• JAMB 2004

For semi conductor to have negative temperature coefficient of resistance implies that

A. Their resistance decrease with temperature
B. The resistance increase with temperature
C. Their resistance is constantly changing with temperature
D. They have electrons and holes at high temperature

Question 8:

• JAMB 2004

In a reverse biased junction diode, current flows in by

A. Positive holes alone
B. Majority carriers
C. Electron alone
D. Minority carriers

Question 9:

• JAMB 2004

Flourescent tubes produces light by the

A. Excitation of gas molecules
B. Conduction of solar energy
C. Refraction of light by gas molecules
D. Thermal agitation of electron in the tubes

Question 10:

• JAMB 2005

When impurities are added to semi-conductors, the conductivity of the semi-conductor

A. Increases then decreases
B. Increases
C. Decreases
D. Remains constant