The conductivity of a semiconductor increases with increase in temperature because
A) number density of free current carriers increases
B) relaxation time increases
C) both number density of carriers and relaxation time increase
D) number density of current carriers increases, relaxation time decreases but effect of decrease in relaxation time is much less than increase in number density
The output of the given circuit is
A. Negatively rectified half wave
B. Positively rectified half wave
C. Negatively rectified full wave
D. Zero all times
The following are the graphs of potential barrier versus width of the depletion region for a p-n junction diode.
Which of the following is correct?
| I | II | III | IV` |
|---|---|---|---|
| A - unbiased diode | A - Forward biased diode | A - unbiased diode | A - unbiased diode |
| B - Reverse biased | B - Reverse biased | B - Forward biased | B - unused diode |
| C - Forward biased | C - unbiased | C - Reverse biased | C - Forward biased |
In a given semiconductor, the ratio of the number density of electron to number density of hole is $$2: 1$$. If $$\frac{1}{7}$$th of the total current is due to the hole and the remaining is due to the electrons, the ratio of the drift velocity of holes to the drift velocity of electrons is :