NEET Physics Nuclei Questions Solved

NEET - 2012

The input resistance of a silicon transistor is

100 $Ω$ . Base current is changed by 40 $μA$

which results in a change in collector current

by 2 mA. This transistor is used as a commom-

emitter amplifier with a load resistance of 4 k $Ω$ .

The voltage gain of the amplifier is

(a) 2000

(b) 3000

(d) 1000

We know

$V_{g} = β \frac{R_{L}}{R_{i}} = \frac{∆ I_{C}}{∆ I_{B}} \frac{R_{L}}{R_{i}} (so, β = \frac{∆ I_{C}}{∆ I_{B}})$

On putting given values

$V_{g} = \frac{2 \times 10^{- 3}}{40 \times 10^{- 6}} \times \frac{4 \times 10^{3}}{100} V_{g} = 2000$

Difficulty Level: