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 (λA/λB) of their wavelengths λA and λB at which the peaks occur in their respective radiation curves is

From Stephan's law: ΔQ/Δt = σεAT4
Given (ΔQ/Δt)A = 104 (ΔQ/Δt)B
σεAATA4 = 104 σεABTB4
(TA/TB)4 = 104 AB/AA
TA/TB = 10(AB/AA)1/4
Given RA/RB = 400
TA/TB = 10(πRB2/πRA2)1/4
TA/TB = 10(1/4002)1/4
TA/TB = 10/20 = 1/2
From wein's displacement law λmT = b
λ ∝ 1/T
λA/λB = TB/TA = 2
Hence, correct answer is 2.