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3.2 Internal energy and energy transfers

3.2 Internal energy and energy transfers

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Question 22

The fuse wire in a mains electrical plug acts as a safety device by melting and breaking the circuit if the safety current rating is exceeded.

a.

Write down the equation that links charge flow, current, and time.

[1]
b.

The fuse wire melts when a charge of 1.84 C1.84\text{ C}1.84 C flows through the fuse in 0.80 s0.80\text{ s}0.80 s. Calculate the current at which the fuse wire melts.

[2]
c.

The mass of the fuse wire is 0.0015 kg0.0015\text{ kg}0.0015 kg. The specific latent heat of fusion of the metal is 210 000 J/kg210\,000\text{ J/kg}210000 J/kg. Calculate the energy needed to melt this fuse wire using the equation:

E=m×L E = m \times L E=m×L
[2]
Markscheme

3.2 Internal energy and energy transfers Questions

  1. GCSE
  2. /Physics
  3. /3.2 Internal energy and energy transfers

37 exam-style questions on AQA GCSE Physics 3.2 Internal energy and energy transfers, covering 3.2.1 Internal energy, 3.2.2 Temperature changes in a system and specific heat capacity, and 3.2.3 Changes of state and specific latent heat. Each one has a worked solution and a mark scheme showing where the marks go.

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