P1 Energy (2) Power, efficiency and energy transfers AQA

What is the definition of efficiency?

• A measure of how much energy is wasted by an appliance

• A measure of how quickly energy is transferred to an appliance

• A measure of the energy transferred usefully to an appliance

• A measure of the energy given off to the surroundings by an appliance

What is the equation used to calculate efficiency?

• Efficiency = total energy input / total energy output

• Efficiency = useful energy output / total energy input

• Efficiency = useful energy input / useful energy output

• Efficiency = total energy input / useful energy output

Which of the following can also be used to calculate efficiency?

• Current

• Voltage

• Mass

• Power

Which key term is used to describe energy being spread out or wasted?

• Efficient

• Deficient

• Dissipate

• Elevate

What term is used to describe a method for reducing unwanted energy transfers by reducing friction?

• Insulation

• Titration

• Lubrication

• Dissipation

What is a thermal insulator?

• A non-conductive material

• A conductive material

What is the name of the method of reducing unwanted energy transfers by the use of non-conductive materials?

• Insulation

• Titration

• Lubrication

• Dissipation

What is the law of conservation of energy?

• Energy is created and transferred

• Energy is created and stored

• Energy is stored and destroyed

• Energy is stored and transferred

How does thermal conductivity of a material affect the rate of conduction across that material?

• The higher the conductivity, the faster the rate of conduction

• The higher the conductivity, the slower the rate of conduction

• The lower the conductivity the faster the rate of conduction

What is the equation linking energy transferred, power and time?​

• Power = energy x time

• Power = energy / time

• Energy = time / power