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Current Electricity question

2021 · 31 Aug · Shift 2 · Q71
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Current Electricity question

2021 · 31 Aug · Shift 2 · Q71

JEE MainPhysicsCurrent ElectricityNumerical+4 / −1
A resistor dissipates 192 J of energy in 1s when a current of 4A is passed through it. Now, when the current is doubled, the amount of thermal energy dissipated in 5s in ‾\underline{\hspace{2cm}}​ J.
Numerical answer
View written solutionFree

Correct answer: 3840

  1. Use Joule’s law of heating

    The thermal energy dissipated in a resistor is H=I2RtH = I^2 R tH=I2Rt

  2. Find the resistance using the first condition

    Given:

    • H=192 JH = 192\,\text{J}H=192J
    • I=4 AI = 4\,\text{A}I=4A
    • t=1 st = 1\,\text{s}t=1s

    So, 192=(4)2R(1)192 = (4)^2 R (1)192=(4)2R(1) 192=16R192 = 16R192=16R R=12 ΩR = 12\,\OmegaR=12Ω

  3. Now current is doubled

    New current: I′=2×4=8 AI' = 2 \times 4 = 8\,\text{A}I′=2×4=8A

    Time: t′=5 st' = 5\,\text{s}t′=5s

    Thermal energy dissipated: H′=(I′)2Rt′H' = (I')^2 R t'H′=(I′)2Rt′ H′=(8)2×12×5H' = (8)^2 \times 12 \times 5H′=(8)2×12×5 H′=64×12×5H' = 64 \times 12 \times 5H′=64×12×5 H′=768×5H' = 768 \times 5H′=768×5 H′=3840 JH' = 3840\,\text{J}H′=3840J

  4. Final Answer

    3840\boxed{3840}3840​

  5. Comparison with stored correct answer

    Stored correct answer = 384038403840

    My derived answer matches the stored answer.

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