Statement-1 : When the temperature of a semiconductor is increased, then its resistance decreases.
Statement-2 : The energy gap between conduction band and valence band is very small for semiconductor.

Options

A. Statement-1 is true, Statement-2 is true, Statement-2 is a correct explanation of Statement-1.
B. Statement-1 is true, Statement-2 is true, Statement-2 is not a correct explanation of Statement-1.
C. Statement-1 is true, Statement-2 is false.
D. Statement-1 is false, Statement-2 is true.

Answer

A

Explanation

When temprature of semiconductor is raised, more covalent bonds are broken. Due to it, large number of electrons and holes are produced in semicoductor. Some electrons move from valence band to conduction band crossing over a very small energy gap and become free electrons. As a result of which the conductivity of semiconductor increases and hence resistance of semiconductor decreases.