The ratio of the resistance of a $P-N$ junction diode in forward bias to its resistance in reverse bias is approximately:

The change in current through a junction diode is $12 \, mA$ when the forward bias voltage is changed by $0.6 \, V$. The dynamic resistance is

The current through the ammeter (neglecting internal resistance) in the following circuit is

An electron in the $n$-region of a $p-n$ junction moves towards the junction with a speed of $5 \times 10^5 \ m/s$. If the barrier potential of the junction is $0.45 \ V$, then the speed with which the electron enters the $p$-region after penetration through the barrier is (Charge of the electron $e = 1.6 \times 10^{-19} \ C$ and mass of the electron $m = 9 \times 10^{-31} \ kg$).

In the following figure,the diodes which are forward biased,are

The cut-in voltage for a silicon diode is approximately $V$.