Thermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law questions with solutions

Showing 1–8 of 8 questions

• IntegermediumThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  A wire of length 10 cm and diameter 0.5 mm radiates 94.2 W at temperature 1727°C. Its emissivity is x/8. Given σ = 6.0×10⁻⁸ W m⁻² K⁻⁴ and π = 3.14, find x.

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  JEE Mains 2025 7 April Morning Shift

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• MCQmediumThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  Two spherical black bodies have radii 0.8 m and 0.2 m and temperatures 400 K and 800 K respectively. Find the ratio P₁/P₂ of their rates of heat loss.

  Options

  • Option A

    8

  • Option B

    4

  • Option C

    2

  • Option D

    1

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  JEE Main 2025 (Online) 22 jan morning Shift

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• NumericdifficultThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  Two identical black-body plates P and Q are at temperatures Tₚ and Tq, with Tq < Tₚ. The net radiative power per unit area from P to Q is W₀. Two identical intermediate plates are then inserted between P and Q, and heat transfer occurs only between adjacent plates. In steady state the power per unit area is Wₛ. Find W₀/Wₛ.

  

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  JEE Advanced 2025 Paper 1

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• MCQmediumThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  A bowl filled with very hot soup cools from 98°C to 86°C in 2 minutes when the room temperature is 22°C. How long will it take to cool from 75°C to 69°C?

  Options

  • Option A

    2 minutes

  • Option B

    1.4 minutes

  • Option C

    0.5 minute

  • Option D

    1 minute

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  JEE Mains25 January 2023Morning Shift

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• MCQeasyThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  A body cools in 7 minutes from 60°C to 40°C. The temperature of the surroundings is 10°C. The temperature of the body after the next 7 minutes is:

  Options

  • Option A

    30°C

  • Option B

    34°C

  • Option C

    32°C

  • Option D

    28°C

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  JEE Mains6 April 2023Shift 2Evening Shift

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• MCQmediumThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  A body cools from 80°C to 60°C in 5 minutes. The surroundings are at 20°C. Using the approximation applied in the source solution, the time to cool from 60°C to 40°C is:

  Options

  • Option A

    500 s

  • Option B

    25/3 s

  • Option C

    450 s

  • Option D

    420 s

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  JEE Mains12 April 2023Shift 1Morning Shift

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• MCQmediumThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  A body cools from 40°C to 24°C in 4 min in surroundings at 16°C. Using the same Newton's-law-of-cooling approximation as the source solution, its temperature after a further 4 min is:

  Options

  • Option A

    20°C

  • Option B

    22°C

  • Option C

    56/3 °C

  • Option D

    17°C

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  JEE Mains 2025 24 Jan Evening Shift

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• NumericmediumThermodynamicsThermal Radiation, Blackbody Radiation and Stefan-Boltzmann Law

  A body cools from 60°C to 40°C in 6 minutes. If temperature of surroundings is 10°C, then after the next 6 minutes, its temperature will be ____ °C.

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  JEE Mains29 January 2023Shift 1Morning Shift

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