p-n junction is a semiconductor diode. It is obtained by bringing p-type semiconductor inclose contact with n-type semiconductor. A thin layer is developed at the p-n junction which is devoid of any charge carrier but has immobile ions. It is called depletion layer. At the junction a potential barrier appears, which does not allow the movement of majority charge carriers across the junction in the absence of any biasing of the junction.
p-n junction offer low resistance when forward biased and high resistance when reverse biased. Read the above paragaph and answer the following question:
(i) Can we measure the potential barrier of p-n junction by putting a sensitive voltmeter across its terminals?
(ii) What practical lesson do you draw from the above study?

Explanation

(i) We cannot measure the potential barrier of p-n junction by putting a sensitive volmeter across its terminals because there are no free electrons or holes in the depletion layer. And in the absence of forward biasing, the depletion layer offers infinite resistance.
(ii) From the above study, we find that when some move supports the tendency of majority of the people, the resistance/(opposition) is lowered and output current (desired result) is large (appreciable). However, when some move is against the tendency of majority of people, it suffers rough weather.