The heat required to raise the temperature of the body by 1k is called?

Analyze the question The question asks for the name of the quantity: the heat needed to raise the temperature of a body (the whole object, not a unit mass) by 1 K.

Explain the concept Here are the key terms and how they differ:

• Heat (thermal) capacity: heat needed to raise the temperature of a whole body by 1 K. Formula: C = Q/ΔT, unit J/K.
• Specific heat capacity: heat needed to raise the temperature of 1 kg of a substance by 1 K. Formula: c = Q/(mΔT), unit J/(kg·K).
• Water equivalent: the mass of water that would absorb the same amount of heat as the body for the same 1 K rise. It is a mass (in kg or g), not an amount of heat.

Solution

1. The question says "a body," so the heat is for the whole object, not per unit mass.
2. That rules out specific heat (A), which is per unit mass.
3. It also rules out water equivalent (C), which is expressed as a mass of water.
4. The definition matches thermal (heat) capacity, since C = Q/ΔT = mc.

For example, if a metal block needs 500 J to rise by 1 K, its thermal capacity is 500 J/K.

Answer The correct option is B. Thermal capacity.

Tip Look for the words "body" or "object" versus "unit mass":

• Whole body → thermal capacity (J/K)
• 1 kg of material → specific heat capacity (J/kg·K)

Also remember C = mc. Thermal capacity is just mass times specific heat capacity.