Physics · May / June 2020 · Paper 42 · Question 3

E = mc∆T in any form OR (E =) mc∆T

efficiency = (energy) output / (energy) input in any form

15 × 4200 × ∆T = 5000 × 3600 × 0.2

(∆T = 5000 × 3600 × 0.2 / 15 × 4200 =) 57 °C

e.g. renewable OR no air pollution OR low running costs OR no named polluting gas OR no greenhouse effect explanation that follows from advantage stated

e.g. expensive to install OR not available at night OR visual pollution OR needs a suitable (roof) space

explanation that follows from disadvantage stated