Q 12-14-049JEE MainJEE Main 2026 (24 Jan, Shift 1)Easy
A voltage regulating circuit consisting of Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W , is operated at 15 V . The approximate value of protective resistance in this circuit is ______ $\Omega$.
Numerical value type. Enter your answer.
Answer: 125
Maximum Zener current: $I = \dfrac PV = \dfrac{0.4}{10} = 0.04$ A.
The resistor drops $15 - 10 = 5$ V:
$$R = \frac{5}{0.04} = 125\ \Omega$$
Solution by Sreeraj P, M.Sc Physics