At 300 K, for a diode current of 1 mA, a certain germanium diode requires a forward bias of 0.1435 V. Where as a certain silicon diode requires a forward bias of 0.718 V. Under the conditions stated above, the closest approximation of the ratio of reverse saturation current in germanium diode to that in silicon diode is

The built-in potential (Diffusion Potential) in a p-n junction

The 6 V Zener diode shown in figure has zero Zener resistance and a knee current of 5 mA. The minimum value of R, so that the voltage across it does not fall below 6 V is:

Referring to the figure. The switch S is in position 1 initially and steady state conditions exist from time t = 0 to t = t₀. At t = t₀, the switch is suddenly thrown into position 2. The current I through the 10K resistor as a function of time t, from t = 0 is (in mA) _____________.

(Give the sketch showing the magnitudes of the current at t = 0, t = t₀ and t = $$\infty$$ )