PhysicsChapter 1: Heat Capacity and Modes of Heat Transfer
Specific Heat Capacity
The **specific heat capacity** of a substance is the thermal energy required to raise the temperature of
Introduction
Different materials require different amounts of thermal energy to produce the same temperature rise. For example, equal masses of water and metal may be supplied with the same amount of energy, but their temperatures may increase by different amounts. This behaviour is described by specific heat capacity.
Definition
The specific heat capacity of a substance is the thermal energy required to raise the temperature of 1 kg of that substance by 1 K or 1°C.
Formula
**Q = mcΔT where: Q = thermal energy transferred, J m = mass, kg c = specific heat capacity, J kg⁻¹ K⁻¹ ΔT = temperature change Rearranging: c = QmΔT**
Understanding the Concept
A material with a high specific heat capacity needs more energy to produce the same temperature increase. Therefore: **High c → more energy needed per degree Low c → less energy needed per degree**
Worked Example
A 2 kg block receives 12,000 J of thermal energy and its temperature rises by 20 K. c = QmΔT c = 120002 × 20 **c = 300 J kg⁻¹ K⁻¹**
Why Water Is Important
Water has a relatively high specific heat capacity. It can absorb a considerable amount of thermal energy without undergoing a very large temperature rise. This makes water useful in cooling systems and contributes to the moderation of temperatures near large bodies of water.
Exam preparation
Exam Focus
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Review the key facts, formulas and checks before you move on.Specific Heat Capacity
Sticky Notes · Quick Revision
SPECIFIC HEAT CAPACITY
- Energy per kg per degree
FORMULA
- Q = mcΔT
HIGH c
- More energy needed
UNIT
- J kg⁻¹ K⁻¹
60-second revision
- Definition: Energy required to raise 1 kg by 1 K.
- Formula: Q = mcΔT
- Unit: J kg⁻¹ K⁻¹
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