When a transistor is used as a switch, it is in:

1.  active state.

2.  cut-off state.

3.  saturation state.

4.  both cut-off and saturation states are possible.

Use of transistor as an amplifier works in the:

1.  Cut off region

2.  Saturation region

3.  Passive region

4.  Active region

For a transistor amplifier, the power gain and voltage gain are 150 and 10 respectively. The current gain is-

1.  $\frac{1}{10}$

2.  $\frac{1}{15}$

3.  15

4.  1500

The conductivity of an n-type semiconductor whose density of conduction electrons is ${\mathrm{n}}_{\mathrm{e}}$, Density of holes is ${\mathrm{n}}_{\mathrm{h}}$, Mobility of conduction electrons is ${\mathrm{m}}_{\mathrm{e}}$and Mobility of holes is ${\mathrm{m}}_{\mathrm{h}},$ will be

1.  $\mathrm{e}\left[{\mathrm{n}}_{\mathrm{e}}{\mathrm{m}}_{\mathrm{h}} + {\mathrm{n}}_{\mathrm{e}}{\mathrm{m}}_{\mathrm{e}}\right]$

2.  $\mathrm{e}\left[{\mathrm{n}}_{\mathrm{e}}{\mathrm{m}}_{\mathrm{e}} + {\mathrm{n}}_{\mathrm{h}}{\mathrm{m}}_{\mathrm{e}}\right]$

3.  ${\mathrm{en}}_{\mathrm{e}}\left[{\mathrm{m}}_{\mathrm{e}} + {\mathrm{m}}_{\mathrm{h}}\right]$

4.  $\mathrm{e}\left[{\mathrm{n}}_{\mathrm{e}}{\mathrm{m}}_{\mathrm{e}} + {\mathrm{n}}_{\mathrm{h}}{\mathrm{m}}_{\mathrm{h}}\right]$

A transistor is used in common emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by 15 $\mu$A and the collector current changes by 1.5 mA. The current gain \(\beta\) will be:

1.  50

2.  48

3.  100

4.  200

$\mathrm{In} \mathrm{the} \mathrm{given} \mathrm{circuit} \mathrm{power}$
$\mathrm{developed} \mathrm{in} 1\mathrm{k\Omega } \mathrm{resistor} \mathrm{is}$

1.  36 mW

2.  12 mW

3.  144 mW

4.  64 mW

In a common emitter transistor amplifier, the audio signal vlotage across the collector is 3V. The resistance of collector is 3k$\Omega$. If current gain is 100 and the base resistance is 2k$\Omega$, the voltage and power gain of the amplifier is 

(1) 200 and 1000

(2) 15 and 200

(3) 150 and 15000

(4) 20 and 2000

What is the output Y in the following circuit, when all the three inputs A,B,C are first 0 and then 1 ?

1. 0,1                   2. 0,0 

3. 1,0                   4. 1,1

To get output 1 for the following circuit, the correct choice for the input is

(1) $A=1, B=0, C=0$       

(2) $A=1, B=1, C=0$

(3) $A=1, B=0, C=1$       

(4) $A=0, B=1, C=0$