JEE Main 2021 · PhysicsNumerical answerNumerical valueEasyCalculation

JEE Main 25 July 2021, Shift 1, Physics Q27

Question 27 of 90 in this shift, Physics question 27 of 30, Section B.

An electric bulb rated as 200 W at 100 V is used in a circuit having 200 V supply. The resistance 'R' that must be put in series with the bulb so that the bulb delivers the same power is _________

\Omega

Official answer

NTA final key.

Chapter: Current Electricity
Topic: Ohm's Law and Resistance
Idea tested: Joule Heating and Power

Same idea in other shifts

Asked 5× in all

3 Apr 2025, Shift 2 · Q39A motor operating on 100 V draws a current of 1 A. If the efficiency of the motor is 91.6%, then the loss of power in units of cal/s isEasySingle correct
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16 Mar 2021, Shift 2 · Q18A resistor develops 500 J of thermal energy in 20 s when a current of 1.5A is passed through it. If the current is increased from 1.5 A to…EasySingle correct
16 Mar 2021, Shift 2 · Q28The energy dissipated by a resistor is 10 mJ in 1 s when an electric current of 2 mA flows through it. The resistance is ________ $\Omega$ .…EasyNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.