The mutual characteristic of a triode is represented by which of the following graphs?

In a diode,when there is a saturation current,the plate resistance will be

The figure represents the variation of triode parameters ($\mu$, $r_p$, or $g_m$) with the plate current. The correct variations of $\mu$ and $r_p$ are given, respectively, by the curves:

With a change of load resistance of a triode, used as an amplifier, from $50 \, k\Omega$ to $100 \, k\Omega$, its voltage amplification changes from $25$ to $30$. The plate resistance of the triode is.....$k\Omega$.

In a diode valve,the cathode temperature must be ($\phi$ = work function):

The amplification factor of a triode is $18$ and its plate resistance is $8 \times 10^{3} \ \Omega$. $A$ load resistance of $10^{4} \ \Omega$ is connected in the plate circuit. The voltage gain will be