Correct answer: 2/3 λₘ
According to Wien's displacement law, the product of the wavelength at which the intensity is maximum (λₘ) and the absolute temperature (T) is constant: λₘT = constant. For T₁ = 2000 K and T₂ = 3000 K, λₘ₂ = λₘ₁ × (T₁/T₂) = λₘ × (2000/3000) = 2/3 λₘ.