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JEE Advanced Physics Thermal Properties of Matter 2025 JEE Advanced 2025 (Paper 1)

JEE Advanced Physics Question (2025) — Solution

Question

Two identical plates P and Q , radiating as perfect black bodies, are kept in vacuum at constant absolute temperatures \( T _ P \) and \( T _ Q \), respectively, with \( T _ Q

Options

  1. A. A
  2. B. B
  3. C. C
  4. D. D

Answer

A. A

Step-by-step solution

Initially : W _0= ( T _ P ^4- T _ Q ^4 ) Finally : Putting heat currents equal in steady state : aligned & ( T _ P ^4- T _1^4 )= ( T _1^4- T _2^4 ) \\ & ( T _1^4- T _2^4 )= ( T _2^4- T _ Q ^4 ) aligned Adding : T _ P ^4- T _1^4= T _2^4- T _ Q ^4 T _1^4+ T _2^4= T _ P ^4+ T _ Q ^4 and T _1^4- T _2^4= T _ P ^4- T _1^4 Adding : T _1^4= 2 ~T _ P ^4+ T _ Q ^4 3 So W _ S = ( T _ P ^4- T _1^4 ) = ( T _ P ^4- ( 2 ~T _ P ^4+ T _ Q ^4 3 ) )= ( T _ P ^4- T _ Q ^4 3 ) hence W _ S W _0 =3

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Related: Physics — Thermal Properties of Matter · All PYQ Banks