Question

The temperature coefficient of resistance of a semiconductor

• A. is always poistive
• B. is always negative
• C. is zero
• D. may be positive or may be negative

Answer 1

The correct option is B

is always negative

Explanation for the correct option:

Option B is always negative

The general definition of the temperature coefficient of resistance is the variation in the resistance value of a substance with regard to each degree of temperature change.

• A semiconductor has a negative temperature coefficient of resistance.
• This indicates that resistance falls off as temperature rises.
• The semiconductor's conductivity rises as a result of the increased number of charge carriers that are available for recombination.

Explanation for the incorrect options:

Option A is always positive

• Conductors have always a positive temperature coefficient of resistance.
• Thus their resistance increases with an increase in temperature.

Option C zero

• A constantan and manganin alloy seems to have a temperature coefficient of resistance that is almost zero.
• Thus there is no change in resistance with temperature.

Option D It may be positive or may be negative

• Positive for conductors and negative for semiconductors.

Thus Option B, is always the negative is the correct option.