1 kilogram of solid X and 1 kilogram of solid Y absorb the same heat; X reaches 15°C and Y reaches 20°C. Compared to X, Y must have a lower

• A. specific heat
• B. conductive heat
• C. heat of fusion
• D. heat of vaporization

Answer: (A)

For this scenario, the key idea is how specific heat determines how much a given amount of heat raises a material’s temperature. The relation q = m c ΔT links the heat added to mass, specific heat, and the temperature change. Here both solids have the same mass (1 kg) and absorb the same heat (q). So q = 1 kg × c × ΔT. Since the substance that ends up hotter has a larger temperature rise, Y’s ΔT is bigger than X’s. With the same q and mass, a larger ΔT means a smaller specific heat c. Therefore Y must have a lower specific heat than X. Energies like heat of fusion or heat of vaporization involve phase changes, not the temperature rise of a solid under a fixed heat input, and conductive heat describes how heat moves rather than how much a substance warms for a given amount of heat.