An electric pump raises water of density ρ \rho\,ρ vertically through a height h h\,h at a constant volume flow rate RRR. The pump motor is connected to a power supply of potential difference V V\,V and draws a current III. The acceleration of free fall is ggg.
Which expression gives the efficiency of the pump system?
VIρRgh\frac{VI}{\rho R g h}ρRghVI
ρRghVIt\frac{\rho R g h}{V I t}VItρRgh
ρRghVI\frac{\rho R g h}{VI}VIρRgh
ρghVIR\frac{\rho g h}{V I R}VIRρgh
84 exam-style questions on AQA A Level Physics Force, energy and momentum, covering Scalars and vectors, Moments, Motion along a straight line, Projectile motion, Newton's laws of motion, Momentum, Work, energy and power, and Conservation of energy. Each one has a worked solution and a mark scheme showing where the marks go.