Engineering
Physics
Radiation
Question

Two spherical stars A and B emit blackbody radiation. The radius of A is 400 times that of B and A emits 104 times the power emitted from B. The ratio (λAλB) of their wavelengths λA and λB at which the peaks occur in their respective radiation curves is

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Solution

rA = 400 rB

PA = 104 PB

PA = σ (4πr2A) TA4

PB = σ (4πrB2) TB4

 PAPB= (400)2 (TATB)4= 104

 (TATB)4=104400×400=14×4=124

 TATB=12                       Now   λ1T

 λAλB=TBTA=2