A zener diode with 5 V zener voltage is used to regulate an unregulated dc voltage input of 25 V . For a 400 Ω resistor connected in series, the zener current is found to be 4 times load current. The load current (I L ) and load resistance (R L ) are :

Physics · Semiconductor and Electronic Devices

JEE Main 2025 — 2 April, Morning Shift — Question 61

A zener diode with 5 V zener voltage is used to regulate an unregulated dc voltage input of 25 V . For a $400 \Omega$ resistor connected in series, the zener current is found to be 4 times load current. The load current $\left(I_{L}\right)$ and load resistance $\left(R_{L}\right)$ are :

Option A:
$I_{L}=20 \mathrm{~mA} ; R_{L}=250 \Omega$
Option B:
$I_{L}=0.02 \mathrm{~mA} ; R_{L}=250 \Omega$
Option C:
$I_{L}=10 \mathrm{~mA} ; R_{L}=500 \Omega$
Correct
Option D:
$I_{L}=10 \mathrm{~A} ; R_{L}=0.5 \Omega$

Answer: C

Step-by-step solution

$5 I_{L}=\frac{(25-5)}{400}=\frac{1}{20}=50 \mathrm{~mA}$

$I_{L}=10 \mathrm{~mA}$

$5=I_{L} R_{L}$ $R_{L}=\frac{5}{I_{L}}=\frac{5}{10 \times 10^{-3}}=500 \Omega$

Answer key and solution verified before publishing.

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Exam: JEE Main 2025
Paper: 2 April, Morning Shift
Subject: Physics
Chapter: Semiconductor and Electronic Devices
Topic: p-n Diode and its Applications