For a transistor, in a common emitter arrangement, the alternating current gain $\mathrm{\beta }$ is given by

(1) $\mathrm{\beta }={\left(\frac{∆{\mathrm{I}}_{\mathrm{c}}}{∆{\mathrm{I}}_{\mathrm{B}}}\right)}_{{\mathrm{V}}_{\mathrm{C}}}$                       

(2) $\mathrm{\beta }={\left(\frac{∆{\mathrm{I}}_B}{∆{\mathrm{I}}_C}\right)}_{{\mathrm{V}}_{\mathrm{C}}}$

(3) $\mathrm{\beta }={\left(\frac{∆{\mathrm{I}}_{\mathrm{c}}}{∆{\mathrm{I}}_E}\right)}_{{\mathrm{V}}_{\mathrm{C}}}$                       

(4) $\mathrm{\beta }={\left(\frac{∆{\mathrm{I}}_E}{∆{\mathrm{I}}_C}\right)}_{{\mathrm{V}}_{\mathrm{C}}}$

The relation between $\mathrm{\alpha }$ and $\mathrm{\beta }$ parameters of current gains for a transistors is given by

(1) $\mathrm{\alpha }=\frac{\mathrm{\beta }}{1-\mathrm{\beta }}$               

(2) $\mathrm{\alpha }=\frac{\mathrm{\beta }}{1+\mathrm{\beta }}$

(3) $\mathrm{\alpha }=\frac{1-\mathrm{\beta }}{\mathrm{\beta }}$               

(4) $\mathrm{\alpha }=\frac{1+\mathrm{\beta }}{\mathrm{\beta }}$

In the CB mode of a transistor, when the collector emitter voltage is changed by 0.5 volt. The collector current changes by 0.05 mA. The output resistance will be 
(1) 10 k$\mathrm{\Omega }$                         

(2) 20 k$\mathrm{\Omega }$

(3) 5 k$\mathrm{\Omega }$                           

(4) 2.5 k$\mathrm{\Omega }$

Consider an NPN transistor amplifier in the common-emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current?
1. 1.1 mA                     

2. 1.01 mA

3. 0.01 mA                   

4. 10 mA

In a common base amplifier the phase difference between the input signal voltage and the output voltage is

(1) 0                     

(2) $\mathrm{\pi }/4$

(3)$\mathrm{\pi }/2$                  

(4) $\mathrm{\pi }$

In NPN transistor the collector current is 10 mA. If 90% of electrons emitted reach the collector, then

(1) Emitter current will be 9 mA

(2) Emitter current will be 11.1 mA

(3) Base current will be 0.1 mA

(4) Base current will be 0.01 mA

In a transistor in CE configuration, the ratio of power gain to voltage gain is 
(1) $\mathrm{\alpha }$                                     

(2) $\mathrm{\beta }/\mathrm{\alpha }$ 

(3) $\mathrm{\beta \alpha }$                                     

(4) $\mathrm{\beta }$ 

Given below are symbols for some logic gates

The XOR gate and NOR gate respectively are 
(a) 1 and 2                  (b) 2 and 3
(c) 3 and 4                  (d) 1 and 4

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

1. 1, 4, 3                     
2. 4, 1, 2
3. 1, 3, 4                   
4. 4, 2, 1

The following truth table corresponds to the logic gate

A  0  0  1  1
B  0  1  0  1
X  0  1  1  1

(1) NAND                     

(2) OR

(3) AND                       

(4) XOR