Equations

Question 1

Change in thermal energy

Answer 1

Change in energy = mass (kg) × specific heat capacity (J/kg°C) × temperature change (°C)

ΔE = mcΔØ

Question 2

Efficiency for any energy transfer

Answer 2

Efficiency = useful output energy transfer / total input energy transfer

Question 3

Efficiency of energy outputs and inputs

Answer 3

Efficiency = useful power output / total power output

Question 4

Potential difference

Answer 4

Potential difference (V) = Currrent (A) × Resistance (Ω)

Question 5

Energy transferred

Answer 5

Energy transferred (J) = power (W) × time (s)

E = Pt

Question 6

Energy Transferred per charge passed

Answer 6

Energy transferred (J) = Charge flow (C) × Potential difference (V)

E = QV

Question 7

Power

Answer 7

Power (W) = Potential difference (V) × Current (A)

P = VI

Question 8

Density

Answer 8

Density (kg/m³) = mass (kg) / volume (m³)

Question 9

Specific latent heat

Answer 9

Specific latent heat (L) = Energy (E) / mass(m)