An electronic micro-actuator on a spacecraft is triggered by melting a thin metallic thermal link.
The thermal link melts when a charge flow of 5.4 C5.4\text{ C}5.4 C passes through it in a time of 0.12 s0.12\text{ s}0.12 s. Calculate the current in the link when it melts. Use the equation: current=charge flowtime\text{current} = \frac{\text{charge flow}}{\text{time}}current=timecharge flow
The mass of the active portion of the thermal link is 0.065 g0.065\text{ g}0.065 g and the specific latent heat of fusion of the metal is 120,000 J/kg120{,}000\text{ J/kg}120,000 J/kg. Calculate the thermal energy needed to melt this portion of the link. Use the equation: energy=mass×specific latent heat\text{energy} = \text{mass} \times \text{specific latent heat}energy=mass×specific latent heat
The thermal link transfers some thermal energy to the surrounding silicon substrate as it heats up and melts. How does transferring energy to the surroundings affect the total electrical energy that must be supplied to melt the link?
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.