An automated 3D printer uses a cartridge heater in its nozzle to melt polylactic acid (PLA) filament for extrusion. The electrical supply to the nozzle heater has an e.m.f., VVV, of 15 V15\text{ V}15 V. The power rating of the heater is 45 W45\text{ W}45 W.
Calculate the resistance, RRR, of the nozzle heater.
The specific latent heat of fusion of the PLA filament is 1.5×105 J kg−11.5 \times 10^5\text{ J kg}^{-1}1.5×105 J kg−1 and its melting point is 180∘C180^\circ\text{C}180∘C.
Define specific latent heat of fusion.
Calculate the maximum mass mmm of PLA filament that the heater could melt in 2.5 minutes2.5\text{ minutes}2.5 minutes.
Explain why the melting process is slower in practice than your answer to (ii) suggests.
26 exam-style questions on OCR A A Level Physics Energy, power and resistance, covering Circuit symbols, E.m.f. and p.d, Resistance, Resistivity, and Power. Each one has a worked solution and a mark scheme showing where the marks go.