UNIT 10: HEAT CAPACITY

• Heat capacity: It is the amount of heat energy required to raise the temperature of a body by 1 ^oC.

  C = E / Δθ
  Δθ represents the difference in temperature (θ₂ – θ₁).

  • Unit: J/^oC.

• Specific heat capacity: It is the amount of heat energy required to raise the temperature of 1 kg of a substance by 1 ^oC.

  c = E / (m Δθ)

  • Unit: J/(kg ^oC)

• Specific heat capacity of different materials is different.

  • For example, 1 kg of copper needs far less energy than 1 kg of water for a temperature rise of 1^oC .

• Experiment to determine the specific heat capacity of a liquid:

  • Use the formula: c = E / (m Δθ)

  • Therefore,

    • Calculate the electrical energy that changes into heat.

    • Measure the mass of liquid.

    • Note the initial and final temperatures.

  • Precautions

    • Use lagging for heat insulation.

    • Stir liquid for uniform distribution of heat.

    • After switching off the heater, allow mercury thread to rise and consider the maximum value to be the final reading.

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