In the circuit shown, if each diode has a forward-biased resistance of 75 $\mathrm{\Omega }$ and infinite resistance in reverse biasing, what will be the values of currents ${\mathrm{i}}_1, {\mathrm{i}}_2, {\mathrm{i}}_3 \mathrm{and} {\mathrm{i}}_4$?

                  

1.  ${\mathrm{i}}_1 = 0.2 \mathrm{A}, {\mathrm{i}}_2 = 0, {\mathrm{i}}_3 = 0.2 \mathrm{A}, {\mathrm{i}}_4 = 0$

2.  ${\mathrm{i}}_1 = 0.26 \mathrm{A}, {\mathrm{i}}_2 = 0, {\mathrm{i}}_3 = 0.26 \mathrm{A}, {\mathrm{i}}_4 = 0$

3.  ${\mathrm{i}}_1 = 0.2 \mathrm{A}, {\mathrm{i}}_2 = 0.07, {\mathrm{i}}_3 = 0.0.7 \mathrm{A}, {\mathrm{i}}_4 = 0.07 \mathrm{A}$

4.  ${\mathrm{i}}_1 = 0.2 \mathrm{A}, {\mathrm{i}}_2 = 0.1, {\mathrm{i}}_3 = 0 \mathrm{A}, {\mathrm{i}}_4 = 0.1 \mathrm{A}$

Doping of a semiconductor (with small traces of impurity atoms) generally changes the resistivity as follows:

1. does not alter

2. increases

3. decreases 

4. may increase or decrease depending on the dopant

Given below are four logic gate symbols (figure). Those for OR, NOR, and NAND are respectively-

1. 

2. 

3. 

4. 

1. 1, 4, 3

2. 4, 1, 2

3. 1, 3, 4

4. 4, 2, 1

In a full-wave rectifier, input ac current has a frequency $\nu$. The output frequency of the current is:

1. $\nu$/2

2. $\nu$

3. 2$\nu$

4. None of these

For the given combination of gates, if the logic states of inputs A, B, C are as follows A=B=C=0, and A =B=1, C=0 then the logic states of output D are:

1. 0, 0

2. 0, 1

3. 1, 0

4. 1, 1

In the network shown, the current flowing through the battery of negligible internal resistance is:

1. 0.10 A

2. 0.15 A

3. 0.20 A

4. 0.30 A

This symbol represents:

1. NOT gate

2. OR gate

3. AND gate

4. NOR gate

In figure assuming the diodes to be ideal:

1. ${\mathrm{D}}_1$ is forward biased and ${\mathrm{D}}_2$ is reverse biased and hence current flows from A to B

2. ${\mathrm{D}}_1$ is reverse biased and ${\mathrm{D}}_2$ is forward biased and hence no current flows from B to A and vice-versa

3. ${\mathrm{D}}_1 \mathrm{and} {\mathrm{D}}_2$ are both forward biased and hence current flows from A to B

4. ${\mathrm{D}}_1 \mathrm{and} {\mathrm{D}}_2$ are both reverse biased and hence no current flows from A to B and vice-versa.

The conductivity of a semiconductor increases with an increase in temperature because:

1. number density of free current carriers increases

2. relaxation time increases

3. both number density of carriers and relaxation time increase

4. number density of carriers increases, relaxation time decreases but the effect of decrease in relaxation time is much less than the increase in number density

A 220 V AC supply is connected between points A and B (figure). What will be the potential difference V across the capacitor?

1. 220 V

2. 110 V

3. 0 V

4. $220\sqrt{2}$V