JEE Main 2022 · 27 Jun · Shift 1 · Physics Q52

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PhysicsInteger+4 / -1Question 52 of 90

A 220 V, 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be ______.

A 25 V, 5 W lamp in series with a resistor R across a 220 V, 50 Hz AC source.

Your answer

Answer and worked solution

Official answer: 975

Lamp. Current $\frac5{25}=0.2$ A and resistance $125\ \Omega$ .

Series resistance. Total $\frac{220}{0.2}=1100\ \Omega$ , so $R=975\ \Omega$ .

Answer: 975

Topics:Electrical power and heating AC basics and RMS values

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JEE Main 2022 · 27 Jun · Shift 1, Physics question 52