Question

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

• A. $35mA$
• B. $30mA$
• C. $40mA$
• D. $20mA$

Answer 1

The correct option is B $30mA$

Net potential across the resistor is difference of the emf and the barrier potential.
$\therefore iR=\epsilon -V_{barrier}=3.5-0.5=3$
$\Rightarrow i=\frac{3}{100}A=30\times {10}^{-3}A=30mA$.