Specific Heat Capacity (Edexcel IGCSE Physics)

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Specific heat capacity

  • The specific heat capacityc of a substance is defined as:

The amount of energy required to raise the temperature of 1 kg of the substance by 1 °C per kilogram of mass (J/kg °C)

  • Different substances have different specific heat capacities
    • If a substance has a low specific heat capacity, it heats up and cools down quickly (ie. it takes less energy to change its temperature)
    • If a substance has a high specific heat capacity, it heats up and cools down slowly (ie. it takes more energy to change its temperature)

Examples of specific heat capacity

Specific heat examples, downloadable AS & A Level Physics revision notes

Low vs high specific heat capacity

  • How much the temperature of a system increases depends on:
    • The mass of the substance heated
    • The type of material
    • The amount of energy put into the system in the form of thermal energy

Calculating specific heat capacity

  • The specific heat capacity of a substance can be calculated using the equatiion:

change space in space thermal space energy space space equals space mass space cross times space specific space heat space capacity space space cross times space change space in space temperature

straight capital delta Q space equals space m c straight capital delta T

  • Where:
    • ΔQ = change in thermal energy, in joules (J)
    • m = mass, in kilograms (kg)
    • c = specific heat capacity, in joules per kilogram per degree Celsius (J/kg °C)
    • ΔT = change in temperature, in degrees Celsius (°C)

Worked example

Water of mass 0.48 kg is increased in temperature by 0.7 °C. The specific heat capacity of water is 4200 J / kg °C.

Calculate the amount of thermal energy transferred to the water.

 

Answer:

Step 1: Write down the known quantities

  • Mass, m = 0.48 kg
  • Change in temperature, ΔT = 0.7 °C
  • Specific heat capacity, c = 4200 J/kg °C

Step 2: Write down the relevant equation 

straight capital delta Q space equals space m c straight capital delta T

Step 3: Calculate the thermal energy transferred by substituting in the values

straight capital delta Q space equals space left parenthesis 0.48 right parenthesis space cross times space left parenthesis 4200 right parenthesis space cross times space left parenthesis 0.7 right parenthesis space equals space 1411.2

Step 4: Round the answer to 2 significant figures

straight capital delta Q space equals space 1400 space straight J

Examiner Tip

This equation will be given on your equation sheet, so don't worry if you cannot remember it, but it is important that you understand how to use it. You will always be given the specific heat capacity of a substance, so you do not need to memorise any values.

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.