Given the same amount of beat, a quantity of water will reach a higher temperature in a brass pot than in a clay pot of the same mass because

Analyze the question: The same amount of heat is supplied, and the pots have the same mass. The water reaches a higher temperature in the brass pot. We need the reason.

Concept: The heat absorbed by a body is

Q = mcΔθ, so Δθ = Q / (mc)

For the same Q and the same m, the temperature rise Δθ is inversely proportional to the specific heat capacity c. A material with a low specific heat capacity heats up more for the same heat input. A material with a high specific heat capacity absorbs more heat to rise by the same amount, so it stays cooler.

Solution:

• The pot absorbs part of the heat, and the rest goes to the water.
• Brass has a specific heat capacity of about 380 J/kg·K. Clay (ceramic) has about 800-900 J/kg·K.
• Since brass has the lower c, the brass pot takes in less heat itself for each degree it rises, so more of the heat goes to the water. The brass pot also conducts heat to the water more quickly.
• The water therefore reaches a higher temperature in the brass pot.

Checking the options:

• A. Density is not the deciding factor here. Wrong.
• B. The rate of expansion has nothing to do with this. Wrong.
• C. If clay lost heat faster, that would be a plausible secondary effect, but it is not the standard explanation, and clay is actually a poor conductor. Wrong.
• D. This says brass has a higher specific heat capacity than clay. That is false, because brass has the lower value. Wrong.
• E. Brass has a lower specific heat capacity than clay. This is correct.

Answer: E

Tip: Remember "low c, quick to heat". Metals such as brass, copper and iron have low specific heat capacities, so they heat up and cool down quickly. Water has a very high c (4200 J/kg·K), so it heats slowly. In any question about the same heat and the same mass, use Δθ = Q/(mc).