A transistor is operated in common emitter configuration at ${\mathrm{V}}_{\mathrm{c}} = 10\mathrm{V}.$ When base current is changed from 10mA to 30mA, it produces a change in emitter current from 2A to 4A, the current amplification factor is

1.  100

2.  99

3.  10

4.  9

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 state and saturation state are possible

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

1. 200 and 1000

2. 15 and 200

3. 150 and 15000

4. 20 and 2000

An n-p-n transistor is connected in the common base configuration in a given amplifier. A load resistance of 800Ω is connected in the collector circuit and the voltage drop across it is 0.8 V. If the current amplification factor is 0.96 and the input resistance of the circuits is 192 Ω the voltage gain and the power gain of the amplifier will respectively be

1. 3.69,3.84
2. 4,4
3. 4,3.69
4. 4,3.84

The device that can act as a complete electronic circuit is

1. Junction diode

2. Integrated circuit

3. Junction transistor

4. Zener diode

The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be

(1) 90                           

(2) 10

(3) 1.25                         

(4) 100

When NPN transistor is used as an amplifier

(1) Electrons move from base to collector

(2) Holes move from emitter to base

(3) Electrons move from collector to base

(4) Holes move from collector to emitter

The phase difference between input and output voltages of a CE circuit is 

(1) 0$°$                         

(2) 90$°$ 

(3) 180$°$                      

(4) 270$°$ 

In a PNP transistor working as a common-base amplifier, current gain is 0.96 and emitter current is 7.2 mA. The base current is:

(1) 0.4 mA                   

(2) 0.2 mA

(3) 0.29 mA                   

(4) 0.35 mA

The transistors provide good power amplification when they are used in 

(1) Common collector configuration

(2) Common emitter configuration

(3) Common base configuration

(4) None of these