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Saturday, 31 October

JEE Main 2024 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 8 April 2024, Shift 2, Physics Q56

Question 56 of 90 in this shift, Physics question 26 of 30, Section B.

A heater is designed to operate with a power of 1000 W in a 100 V line. It is connected in combination with a resistance of 10 Ω10\ \Omega and a resistance R, to a 100 V mains as shown in figure. For the heater to operate at 62.5 W, the value of R should be __________ Ω\Omega.

The figure, in words

Circuit: 100 V source in a loop with a 10 Ω10\ \Omega resistor in series, then between points B and C the heater in parallel with resistance R.

Official answer

5

NTA final key.

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

Same idea in other shifts

Asked 15× in all
  1. 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
  2. 4 Apr 2024, Shift 2 · Q42An electric bulb rated 50 WW - 200 VV is connected across a 100 VV supply. The power dissipation of the bulb is:EasySingle correct
  3. 8 Apr 2024, Shift 2 · Q41Water boils in an electric kettle in 20 minutes after being switched on. Using the same main supply, the length of the heating element…MediumSingle correct
  4. 31 Jan 2024, Shift 2 · Q41By what percentage will the illumination of the lamp decrease if the current drops by 20%?EasySingle correct
  5. 13 Apr 2023, Shift 1 · Q50Different combination of 3 resistors of equal resistance R are shown in the figures. The increasing order for power dissipation is: (A)…MediumDiagram basedHas a figure
  6. 13 Apr 2023, Shift 1 · Q60A potential VoV_o is applied across a uniform wire of resistance R. The power dissipation is P1P_1. The wire is then cut into two equal…EasyNumerical value
  7. 28 Jul 2022, Shift 2 · Q26An electrical bulb rated 220 V, 100 W, is connected in series with another bulb rated 220 V, 60 W. If the voltage across combination is…MediumNumerical value
  8. 25 Jun 2022, Shift 1 · Q57A resistor develops 300 J of thermal energy in 15 s, when a current of 2 A is passed through it. If the current increases to 3 A, the…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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.