Question

When a potential difference is applied across, the current passing through
A. an insulator at 0 K is zero
B. a semiconductor at 0 K is zero
C. a metal at 0 K is zero
D. a reverse biased p-n junction diode at 300 K is finite

Answer 1

Correct Answer - C
At OK, if the same P.D. is applied across an insulator or a semiconductor the current is zero. (The semiconductor also becomes a perfect insulator at OK.) Similarly, in the reverse biased p-n junction diode, a small current flows due to minority charge carriers. Thus (a), (b), (d) are correct. But (c) is wrong because at OK, a conductor becomes a super conductor and the current in it is very large (infinite).