Efficiency & Energy Resources Practice Questions

Which of these is a renewable energy resource?

Put a cross ( ☒ ) in the box next to your answer.

☐ A coal

☐ B nuclear fuel

☐ C crude oil

☐ D bio-fuel

Energy resources are used for purposes other than generating electricity.

Give one use of a non-renewable energy resource in transport and one use of a renewable energy resource for heating a home.

Calculate the efficiency of the drill.

efficiency = ..............................................................

Explain why the efficiency of the drill is less than 1 (100%).

Name the energy store that energy is transferred to as the chain becomes warm.

Explain how putting oil on the chain reduces the unwanted energy transfer.

Using the data in the table, describe the trends in the UK's use of energy resources for generating electricity between 2010 and 2022, and explain why these changes have happened.

Calculate the efficiency of the LED lamp as a percentage.

efficiency = .............................................................. %

In the same time, a filament lamp is supplied with $3600\ \mathrm{J}$ of energy. The filament lamp is $5\%$ efficient.

Calculate the energy transferred usefully by the filament lamp.

energy transferred usefully = .............................................................. J

The petrol engine of a go-kart has an efficiency of $0.24$.

In one race the engine does $7200\ \mathrm{J}$ of useful work in moving the go-kart.

Calculate the energy supplied to the engine by the fuel.

energy supplied by the fuel = .............................................................. J

A builder is going to fill the gap between the two walls of a house with one of these materials.

Using the table, state which material the builder should choose to reduce the rate of cooling of the house as much as possible. Explain your answer.

The builder also considers making the outside walls of the house thicker.

Describe the effect of increasing the thickness of the walls on the rate of cooling of the house.

State which material is the best insulator.

Give one variable, other than the starting temperature of the water, that the student must control in this investigation.

Explain how wrapping the can in bubble wrap reduces the rate at which the water cools.

Calculate the efficiency of the charging process.

efficiency = ..............................................................

When the car is driven, the motor transfers $85\%$ of the energy from the battery usefully to the wheels.

Calculate the overall efficiency of the whole process, from the mains supply to the useful energy transferred to the wheels.

overall efficiency = ..............................................................

Calculate the efficiency of the pulley system.

efficiency = ..............................................................

Give two reasons, other than friction, why energy is wasted when the builder uses this pulley system.