Different voltages are applied across a P-N junction and the currents are measured for each value. Which of the following graphs is obtained between voltage and current?

1. 

2. 

3. 

4. 

If the following input signal is sent through a PN-junction diode, then the output signal across ${\mathrm{R}}_{\mathrm{L}}$ will be

1. 

2. 

3. 

4. 

The curve between charge density and distance near P-N junction will be

1. 

2. 

3. 

4. 

The resistance of a germanium junction diode whose is shown in figure is $\left({\mathrm{V}}_{\mathrm{k}}=0.3\mathrm{V}\right)$

(1) 5 k$\mathrm{\Omega }$

(2) 0.2 k$\mathrm{\Omega }$

(3) 2.3 k$\mathrm{\Omega }$

(4) $\left(\frac{10}{2.3}\right)\mathrm{k\Omega }$

In the half-wave rectifier circuit shown. Which one of the following wave forms is true for ${\mathrm{V}}_{\mathrm{CD}}$, the output across C and D?

1. 

2. 

3. 

4. 

A full-wave rectifier circuit along with the input and output voltages is shown in the figure.

The contribution to the output voltage from diode – 2 is :

(1) A, C                       

(2) B, D

(3) B, C                       

(4) A, D

The i-V characteristic of a P-N junction diode is shown below. The approximate dynamic resistance of the P-N junction when a forward bias of 2 volt is applied

(1) 1 $\mathrm{\Omega }$

(2) 0.25 $\mathrm{\Omega }$ 

(3) 0.5 $\mathrm{\Omega }$

(4) 5 $\mathrm{\Omega }$

The given figure shows the wave forms for two inputs A and B and that for the output Y of a logic circuit. The logic circuit is 

(1) An AND gate                   

(2) An OR gate

(3) A NAND gate                   

(4) An NOT gate

The variation of anode current in a triode corresponding to a change in grid potential at three different values of the plate potential is shown in the diagram. The mutual conductance of the triode is 

1.  2.5 m mho 
2.  5.0 m mho
3.  7.5 m mho     
4.  10.0 m mho

A silicon specimen is made into a P-type semi-conductor by dopping, on an average, one Indium atom per $5\times {10}^7$ silicon atoms. If the number density of atoms in the silicon specimen is $5\times {10}^{28} \mathrm{atoms}/{\mathrm{m}}^3$ then the number of acceptor atoms in silicon per cubic centimeter will be:

(1) $2.5\times {10}^{30} \mathrm{atoms}/{\mathrm{cm}}^3$                  

(2) $1.0\times {10}^{13} \mathrm{atoms}/{\mathrm{cm}}^3$

(3) $1.0\times {10}^{15} \mathrm{atoms}/{\mathrm{cm}}^3$                   

(4) $2.5\times {10}^{36} \mathrm{atoms}/{\mathrm{cm}}^3$