The mutual characteristic curves of a triode are as shown in the figure. The cut-off voltage for the triode is.....$V$.

In a triode valve,which of the following statements is correct?

If ${R_p} = 7 \text{ k}\Omega$ and ${g_m} = 2.5 \text{ millimho}$, then on increasing the plate voltage by $50 \text{ V}$, how much must the grid voltage be changed so that the plate current remains the same? (in $V$)

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

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 $\text{mA}$.

For a triode, ${r_p} = 10 \text{ k}\Omega$ and ${g_m} = 3 \text{ m}\mho$. If the load resistance is double the plate resistance, then the value of the voltage gain will be: