$NPN$ transistors are preferred to $PNP$ transistors because they have

$A$ working transistor with its three legs marked $P, Q$ and $R$ is tested using a multimeter. No conduction is found between $P$ and $Q$. By connecting the common (negative) terminal of the multimeter to $R$ and the other (positive) terminal to $P$ or $Q$,some resistance is seen on the multimeter. Which of the following is true for the transistor?

$A$ transistor is used in common emitter mode as an amplifier. Then:

For a constant collector-emitter voltage of $8\,V$,the collector current of a transistor changed from $4\,mA$ to $6\,mA$,whereas the base current changed from $20\,\mu A$ to $25\,\mu A$. If the transistor is in the active state,the small signal current gain (current amplification factor) will be:

In the figure,given that $V_{BB}$ supply can vary from $0$ to $5.0 \,V$,$V_{CC} = 5\,V$,$\beta_{dc} = 200$,$R_B = 100\,k\Omega$,$R_C = 1\,k\Omega$ and $V_{BE} = 1.0\,V$. The minimum base current and the input voltage at which the transistor will go to saturation,will be respectively:

The ratio $(R)$ of output resistance $r_0$ and input resistance $r_i$ in measurements of input and output characteristics of a transistor is typically in the range: