Question

Diode is forward bias and the applied voltage is greater than the potential barrier then
resistance of the junction in the forward bias decreases.
the potential barrier remains the same.
the width barrier remains decreased.
p-type is at higher potential than the n-type.
all are true
all are false
I,III,IV are true
I,II,III are true

Answer 1

Hint: Diode: A diode is defined as a two terminal electronic component that only conducts current in one direction, so long as it is operated in specific voltage. There are seven types of diode- light emitting diode (LED), laser diode, Avalanche diode, Zener diode, schottky diode, photodiode, p-n junction diode. Silicon and germanium is generally used in diodes.

Complete step by step solution:
p-type and n-type semiconductor are created by doping. Doping is used as the mixing of impurity in any atom. The p-type refers to the positive charge carrier where n-type refers to the negative charge carrier. In p-type holes concentration is higher than electron concentration, holes are the majority charge carriers and electrons are minority carriers. In n-type electron concentration is higher than the holes concentration, electrons are the majority charge carriers and holes are minority carriers.
In forward bias the p-n junction diode, p-type is connected to the positive terminal of the battery whereas the n-type is connected to the negative terminal of the battery. In reverse bias the p-n junction diode, p-type is connected to the negative terminal of the battery whereas the n-type is connected to the positive terminal of the battery.
When the applied potential is higher than the barrier potential, charge carries i.e, the holes in the p-type region and the electrons in the n-type region pushed towards the junction. This reduces the width of the depletion region. With increasing forward biasing voltage, the depletion region becomes thin; it cannot counter the charge from moving across the p-n junction. As a consequence reducing the electrical resistance.
So the answer is (C) I,III,IV are true.

Note: The ideal diode offers zero resistance. Application of diodes are- rectifier, clipping circuit, logical gates, reverse current protection. Diodes show three types of characteristics- forward biased, reverse biased and zero biased. Photodiode is used in making solar panels and light emitting diodes (LED) produces coherent light.