1
MCQ (Single Correct Answer)
The conductivity of a semiconductor increases with increase in temperature, because
A
number density of free current carries increases
B
relaxation time increases
C
both number density of carries and relaxation time increase
D
number density of carries increases, relaxation time decreases but effect of decrease in relaxation time is much less than increase in number density
2
MCQ (Single Correct Answer)
In figure given below $V_0$ is the potential barrier across a $p-n$ junction, when no battery is connected across the junction
A
1 and 3 both correspond to forward bias of junction
B
3 corresponds to forward bias of junction and 1 corresponds to reverse bias of junction
C
1 corresponds to forward bias and 3 corresponds to reverse bias of junction
D
3 and 1 both correspond to reverse bias of junction
3
MCQ (Single Correct Answer)
In figure given below, assuming the diodes to be ideal
A
$D_1$ is forward biased and $D_2$ is reverse biased and hence current flows from $A$ to $B$
B
$D_2$ is forward biased and $D_1$ is reverse biased and hence no current flows from $B$ to $A$ and vice-versa
C
$D_1$ and $D_2$ are both forward biased and hence current flows from $A$ to $B$
D
$D_1$ and $D_2$ are both reverse biased and hence no current flows from $A$ to $B$ and vice-versa
4
MCQ (Single Correct Answer)
A 220 V AC supply is connected between points $A$ and $B$ (figure). What will be the potential difference $V$ across the capacitor?
A
220 V
B
110 V
C
0 V
D
220$\sqrt2$ V
5
MCQ (Single Correct Answer)
Hole is
A
an anti-particle of electron
B
a vacancy created when an electron leaves a covalent bond
C
absence of free electrons
D
an artificially created particle