Find the current through the $40 \Omega$ resistor in the given circuit having a diode, three resistors and two cells.

In a PN junction diode, the forward bias is increased gradually from 0 Volt to 1 Volt. Which of the following statements is correct?

A. The depletion width increases, and barrier potential increases

B. The depletion width decreases, but the electric field inside the junction increases

C. The depletion width remains unchanged, but current increases

D. The depletion width decreases and barrier potential decreases

A silicon sample is doped simultaneously with donor impurity phosphorus at a concentration of $N_D=3 \times 10^{22} \mathrm{~m}^{-3}$ and acceptor impurity boron at a concentration of $N_D=2.8 \times 10^{22} \mathrm{~m}^{-3}$. The intrinsic carrier concentration of silicon at room temperature is $n_i=1.5 \times 10^{16} \mathrm{~m}^{-3}$. Assuming complete ionization, the hole concentration is :

In the circuit given, the reverse breakdown voltage of the Zener diode is 4.8 V . The current through the Zener and the power dissipation in Zener is: