52. In the given figure, a diode D is connected to an external resistance R = 100Ω 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 :

52. In the given figure, a diode D is connected to an external resistance R = 100Ω 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 :

(a) 40 mA

(b) 20 mA

(c) 35 mA

(d) 30 mA

Answer :  (d) 30 mA

\( V = V_1 + V_2 \)

\( 3.5 = 0.5 + V_R \)

\( V_R = 3\,\text{V} \)

\( V = IR \)

\( i = \frac{V}{R} = \frac{3}{100} \)

\( = \frac{3 \times 10}{1000} \)

\( = \frac{30}{1000} = 30 \times 10^{-3}\,\text{A} \)

\( = 30\,\text{mA} \)