Question

Current in the circuit will be (in amperes):

• A. $\frac{5}{40}$
• B. $\frac{5}{50}$
• C. $\frac{5}{10}$
• D. $\frac{5}{20}$

Answer 1

The correct option is B $\frac{5}{50}$

Let the potentials of the leftmost points on the circuit be $V$ each and that on the rightmost points be $0$ as shown in the figure.


For the top branch of the circuit: Current cannot pass from higher potential to lower potential through this diode as this is reverse bias diode. Hence we can replace this branch with an open circuit.

For the middle branch: Current will pass from higher potential to lower potential of this diode as this is a forward bias diode and hence we can replace this portion with a closed path.


Hence the equivalent circuit has a battery of $5V$ and two resistances in series of $20\Omega$ and $30\Omega$.
Therefore,
$i=\frac{V}{R}=\frac{5}{50}A$