Two solid bars of identical length and cross-section connect a hot reservoir at to a…
PHYSICS · Single correct · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
Two solid bars of identical length and cross-section connect a hot reservoir at 100∘C to a cold reservoir at 0∘C. Bar P is copper; bar Q is glass. After the same time interval, which statement best compares the energy transferred through the two bars?
(a) Bar P transfers less energy primarily because copper’s smaller specific heat means it can absorb the temperature difference without passing along much heat.
(b) Both bars transfer the same energy because the temperature difference and their dimensions are identical, so the heat lost by the hot reservoir must equal the heat gained by the cold reservoir regardless of material.
(c) Bar P transfers more energy primarily because copper has a much larger thermal conductivity than glass.
(d) Bar Q transfers more energy primarily because glass’s lower density allows its molecules to move faster and carry heat more readily.