| 1. | number density of free current carries increases | 
| 2. | relaxation time increases | 
| 3. | both number density of carries and relaxation time increase | 
| 4. | number density of current carriers increases, relaxation time decreases but the effect of decrease in relaxation time is much less than the increase in number density | 

| 1. | \(1\) and \(3\) both correspond to forward bias of junction. | 
| 2. | \(3\) corresponds to forward bias of junction and \(1\) corresponds to reverse bias of junction. | 
| 3. | \(1\) corresponds to forward bias and \(3\) corresponds to reverse bias of junction. | 
| 4. | \(3\) and \(1\) both correspond to reverse bias of junction. | 
| 1. | \(D_1\) is forward biased and \(D_2\) is revers-biased and hence current flows from \(A\) to \(B\). | 
| 2. | \(D_2\) is forward biased and \(D_1\) is reverse-biased and hence no current flows from \(B\) to \(A\) and vice-versa. | 
| 3. | \(D_1\) and \(D_2\) are both forward-biased and hence current flows from \(A\) to \(B\). | 
| 4. | \(D_1\) and \(D_2\) are both reverse-biased and hence no current flows from \(A\) to \(B\) and vice-versa. | 
                
| 1. | \(220~\text{V}\) | 2. | \(110~\text{V}\) | 
| 3. | \(0~\text{V}\) | 4. | \(220\sqrt{2}~\text{V}\) | 
Hole is:
| 1. | an anti-particle of electron. | 
| 2. | a vacancy created when an electron leaves a covalent bond. | 
| 3. | absence of free electrons. | 
| 4. | an artificially created particle. | 
The output of the given circuit in figure given below,
           
| 1. | would be zero at all times. | 
| 2. | would be like a half wave rectifier with positive cycles in output. | 
| 3. | would be like a half wave rectifier with negative cycles in output. | 
| 4. | would be like that of a full wave rectifier. | 
In the circuit shown in the figure given below, if the diode forward voltage drop is \(0.3~\text V,\) the voltage difference between \(A\) and \(B\) is:
                   
| 1. | \(1.3~\text V\) | 2. | \(2.3~\text V\) | 
| 3. | \(0\) | 4. | \(0.5~\text V\) | 
A truth table for the given circuit is:
  
 
| 1. | \(A\) | \(B\) | \(E\) | 2. | \(A\) | \(B\) | \(E\) | 
| \(0\) | \(0\) | \(1\) | \(0\) | \(0\) | \(1\) | ||
| \(0\) | \(1\) | \(1\) | \(0\) | \(1\) | \(0\) | ||
| \(1\) | \(0\) | \(1\) | \(1\) | \(0\) | \(0\) | ||
| \(1\) | \(1\) | \(0\) | \(1\) | \(1\) | \(0\) | ||
| 3. | \(A\) | \(B\) | \(E\) | 4. | \(A\) | \(B\) | \(E\) | 
| \(0\) | \(0\) | \(0\) | \(0\) | \(0\) | \(0\) | ||
| \(0\) | \(1\) | \(1\) | \(0\) | \(1\) | \(1\) | ||
| \(1\) | \(0\) | \(0\) | \(1\) | \(0\) | \(1\) | ||
| \(1\) | \(1\) | \(1\) | \(1\) | \(1\) | \(0\) | ||
| (a) | electrons move from lower energy level to higher energy level in the conduction band. | 
| (b) | electrons move from higher energy level to lower energy level in the conduction band. | 
| (c) | holes in the valence band move from higher energy level to lower energy level. | 
| (d) | holes in the valence band move from lower energy level to higher energy level. | 
Choose the correct option:
1. (a), (c)
2. (a), (d)
3. (b), (d)
4. (c), (d)
In the depletion region of a diode:
| (a) | there are no mobile charges | 
| (b) | equal number of holes and electrons exist, making the region neutral | 
| (c) | recombination of holes and electrons has taken place | 
| (d) | immobile charged ions exist | 
1. (a), (b)
2. (a), (b), (d)
3. (c), (d)
4. All options are correct