Question

The I-V characteristics of a p-n junction diode is shown. What is the resistance of the junction when a forward bias of 2 V is applied?

(a) 20 Ω

(b) 40 Ω

(c) 60 Ω

(d) 80 Ω

The question was asked in an interview.

I need to ask this question from Characteristics of P-N Junction in chapter Semiconductors of Engineering Physics II

Answer 1

Correct answer is (b) 40 Ω

To explain: The current at 2 V is 5 mA and at 2.2 V it is 10 mA.

The dynamic resistance is: Δ V/Δ I

= 0.5/5 X 10^3 Ω

= 40 Ω.