Question

Assertion: The resistivity of the semiconductor increases with temperature.
Reason: The atoms of semiconductor vibrate with larger amplitude at higher temperature thereby increasing its resistivity.

a. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
b. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is incorrect but Reason is correct
d. Both Assertion and Reason are incorrect

Answer 1

Hint: Start explaining the conductor and inductor in brief. Explain then about the semiconductors. Make a brief explanation on conduction bands in semiconductors. Compare how the number of free electrons increases with temperature. On reading the above statement determines whether the reason and assertion is true.

Complete step by step solution:
Conductors are materials that contain a lot of electrons and the flow of the current is necessary for the flow of electrons in the material. Hence, we can say that conductors have less resistance. Insulators are materials that have no free electrons, and then we can say that insulators have high resistance. Semiconductors have resistivity between conductors and insulators.

Semiconductors conduct electricity when introduced to the impurities. The impurities could be a pentavalent type or trivalent type. Introducing a pentavalent impurity will result in n type semiconductor and introducing a trivalent impurity will result in p type semiconductor. Conductor band is the one in which free electrons conduct electricity.

The conductivity increases with temperature in a semiconductor. As the temperature increases, the electrons in the valence band gain enough thermal energy to jump to the conduction band. When the number of electrons in the conduction band increases, the conductivity also increases and resistivity decreases. Both assertion and reason are incorrect.

Hence, the correct answer is option (D).

Note: Conductivity changes due to the presence in impurities in semiconductors. The impurities could be a pentavalent type or trivalent type. Introducing a pentavalent impurity will result in n type semiconductor and introducing a trivalent impurity will result in p type semiconductor. Tap water is a conductor. Pure water does not conduct electricity but the tap water with impurities will conduct electricity.