Transistor as an Amplifier

Q.

In an NPN power transistor, the emitter current is $20mA$. If $98\%$ of the electrons injected in to the base region reach the collector, the base current is nearly

1. $2mA$

2. $1mA$

3. $0.6mA$

4. $0.4mA$

Q.

An alternating current having a peak value of $14A$ is used to heat a metal wire. To produce the same heating effect, a constant current $I$ can be used, where $I$ is

1. $14A$

2. About $20A$

3. $7A$

4. About $10A$

Q. For the transistor circuit shown, $\beta =100$ and voltage drop between emitter and base is $0.7V$. The value of $V_{CE}$ will be

1. $10V$
2. $5V$
3. $13V$
4. $0V$

Q. In a common-emitter amplifier, using output resistance of $5000\text{ohm}$ and input resistance of $2000\text{ohm}$, if the peak value of input signal voltage is $10\text{mV}$ and $\beta =50$, then the power gain is

1. $625\text{W}$
2. $25\text{W}$
3. $6250\text{W}$
4. $125\text{W}$

Q. What is the emitter current if $I_B=20\mu A$ and $\beta =100$ ?

1. $2.02mA$
2. $2.00mA$
3. $1.01mA$
4. $120mA$