question_answer

In the given figure, a diode D is connected to an external resistance \[R=100\,\Omega \] and an, e.m.f of 3.5 V. If the barrier potential developed across the diode is 0.5 V, the current in the circuit will be         [NEET (Re) 2015]

A)  30 mA             

B)  40 mA

C)  20 mA             

D)       35 mA

Correct Answer: A

Solution :

           

Given, external resistance \[R=100\,\Omega \] and an emf is 3.5 V.

Potential barrier across the diode is 0.5 V,

Potential difference on

\[R=3.5V-0.5V=3.0V\]

Current in circuit,

\[I=\frac{V}{R}=\frac{3}{100}=0.03A=30mA\]