The principle quantum number $n$ corresponding to the exited state of $\mathrm{He}^{+}$ion. If on transition to the ground state two photons in succession with wavelength $1026 \mathop {\rm{A}}\limits^{\rm{o}}$ and $304 \mathop {\rm{A}}\limits^{\rm{o}}$ are emitted $\left(R=1.097 \times 10^{-7} \mathrm{~m}^{-1}\right)$

$$ \text { Truth table for the given circuit is } $$

If $R_C$ and $R_B$ are respectively the resistances of in collector and base sides of the circuit and $\beta$ is the current amplification factor, then the voltage gain of a transistor amplifier in common emitter configuration is