In an intrinsic semiconductor, the concentration of electron-hole pair is ${10}^{16} {\mathrm{m}}^{-3}$. Due to doping, electron concentration becomes ${10}^{22} {\mathrm{m}}^{-3}$. After doping, the hole concentration is ${10}^{\mathrm{n}} {\mathrm{m}}^{-3}$ . Value of $n$, is

In the circuit, the current through Zener diode is $n \mathrm{mA}$. Value of $n$, is (the breakdown voltage is $10 \mathrm{V}$)

A Zener diode of power rating $2 \mathrm{W}$ is to be used as a voltage regulator. If Zener has a breakdown of$5 \mathrm{V}$ and it is being fed with voltage fluctuating between $3 \mathrm{V}$ and$7 \mathrm{V}$, what should be value of $R$ for self operation?

A transistor in $\mathrm{CE}$ mode is given in the figure. If, $\mathrm{\beta }=100 \&$ $i_c= 2 \mathrm{mA}$. The value of ${\mathrm{V}}_{\mathrm{CE}}$ (in $\mathrm{V}$) (symbols have their usual meaning)

The circuit contains two diodes each with a forward resistance of $50 \mathrm{\Omega }$ and with infinite reverse resistance. The current (in $\mathrm{A}$) through $100 \mathrm{\Omega }$ resistor is