NEET Physics Semiconducting Devices NEET PYQ-Semiconducting Devices

In which of the following figures, junction diode is forward biased                              [AIPMT 2000]

A)

B)

C)

D)

Correct Answer: B

Solution :

Key Idea: In forward biasing of p-n junction p-side is given more positive voltage than n-side.

For forward biasing of p-n junction, p-side should be at higher potential than n-side. Now we apply this rule to the four options.

Here, p-side is at lower potential (OV) and n-side at higher potential (2V). So this diode is not forward biased.

Here, p-side is at higher potential (OV) and n-side at lower potential\[(-2V)\]. So, this diode is forward biased.

Here, p-side is at lower potential \[(-2V)\] and n-side at higher potential (OV). So, this diode is not forward biased.

Here p-side is at lower potential (2V) and n-side at higher potential (5V). So, this is not forward biased.

Hence, choice is correct.