A metal rod is gradually heated in a dark room so that its temperature increases…
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A metal rod is gradually heated in a dark room so that its temperature increases smoothly from room temperature to a bright yellow glow. Throughout the process the rod is assumed to emit radiation like an ideal thermal emitter.
(a) Describe qualitatively how the peak wavelength of the emitted radiation changes as the rod is heated. In your description, relate the direction of this shift to the corresponding change in temperature.
(b) Explain why the rod first appears dull red, then orange, and eventually yellow-white as its temperature rises, even though it continuously emits radiation across the entire visible spectrum.
(c) A student claims that doubling the absolute temperature of the rod would double the peak wavelength of its emission spectrum. Evaluate the validity of this claim using appropriate physical reasoning.