An electrical appliance is protected by a fuse containing a thin metal wire.
The wire in the fuse melts when a charge flow of 3.5 C3.5\text{ C}3.5 C passes through it in a time of 0.50 s0.50\text{ s}0.50 s. Calculate the current in the wire when it melts. Use the equation: current=charge flowtime\text{current} = \frac{\text{charge flow}}{\text{time}}current=timecharge flow
The mass of the fuse wire is 0.024 g0.024\text{ g}0.024 g and the specific latent heat of fusion of the wire is 85,000 J/kg85{,}000\text{ J/kg}85,000 J/kg. Calculate the thermal energy needed to melt the wire. Use the equation: energy=mass×specific latent heat\text{energy} = \text{mass} \times \text{specific latent heat}energy=mass×specific latent heat
The fuse transfers some energy to its surroundings as it heats up and melts. How does transferring energy to the surroundings affect the total energy that must be supplied to melt the fuse?
Practise AQA GCSE Physics Internal energy and energy transfers with exam-style questions for Foundation and Higher tier. 48 questions covering Internal energy, Temperature changes in a system and specific heat capacity, and Changes of state and specific latent heat, matched to the AQA GCSE Physics (8463) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.