Question

A black body is at a temperature of 2880 K. The energy of radiation emitted by this object with wavelength between 499 nm and 500 nm is U₁, between 999 nm and 1000 nm is U₂ and between 1499 nm and 1500 nm is U₃. The Wien's constant $b = 2.88 \times 10^{6}nmK$. Then

• A. U₁ = 0
• B. U₃ = 0
• C. U₁ > U₂
• D. U₂ > U₁

Answer 1

Answer: (D)

U₂ > U₁

Answer 2

According to Wien's displacement law $\lambda_{m}T = b$

∴ $\lambda_{m} = \frac{b}{T} = \frac{2.88 \times 10^{6}nm ⥂ - ⥂ K}{2880nm} = 1000nm$

i.e. energy corresponding to wavelength 1000 nm will be maximum i.e. U₂ will be maximum U₁ < U₂ > U₃

Energy distribution graph with wavelength will be as

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