The grid voltage of any triode valve is changed from $-1 \, V$ to $-3 \, V$ and the mutual conductance is $3 \times 10^{-4} \, \text{mho}$. The change in plate circuit current will be ..... $mA$.

$A$ triode has a transconductance $(g_m)$ of $2.5 \text{ mA/V}$ and an anode resistance $(r_p)$ of $20 \text{ k}\Omega$. If it is used as an amplifier with an amplification factor of $10$, what is the load resistance $(R_L)$ connected to the plate circuit in $\text{k}\Omega$?

In the grid circuit of a triode, an input voltage $E = 2\sqrt{2} \cos \omega t$ is applied. If the amplification factor $\mu = 14$ and the plate resistance $r_p = 10 \text{ k}\Omega$, find the $r.m.s.$ current flowing through the load resistance $R_L = 12 \text{ k}\Omega$ in $\text{mA}$.

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

In an electron gun,the control grid is given a negative potential relative to the cathode in order to:

Which of the following does not vary with plate or grid voltages in a vacuum triode?