In a semiconductor;

(A)	there are no free electrons at \(0^\circ\text{K}.\)
(B)	there are no free electrons at any temperature.
(C)	the number of free electrons increases with temperature.
(D)	the number of free electrons is less than that in a conductor.

Choose the correct option from the given ones:

1.	(A) and (B) only
2.	(B) and (C) only
3.	(A), (C), and (D) only
4.	(A), (B), and (D) only

When an impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor:
1. increases
2. decreases
3. remains the same
4. becomes zero

A \(\mathrm{p}\text-\)type of semiconductor is:
1. positively charged
2. negatively charged
3. uncharged
4. uncharged at \(0~\text{K}\) but charged at higher temperatures

Let \(n_{p}\) and \(n_{e}\) be the number of holes and conduction electrons in an intrinsic semiconductor. Then:
1. \(n_{p}> n_{e}\)
2. \(n_{p}= n_{e}\)
3. \(n_{p}< n_{e}\)
4. \(n_{p}\neq n_{e}\)