Energy questions

By Interwoven Maths

Energy question collection

Review Energy questions for Physics, with correct answers shown and coverage across energy stores and transfers; conservation of energy; efficiency and power.

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Question 1

What does one joule (J) measure?
  1. Energy transferred
  2. Electric current
  3. Force
  4. Power rating

Question 2

Which unit is used for power?
  1. Watt (W)
  2. Joule (J)
  3. Newton (N)
  4. Coulomb (C)

Question 3

A \(2\,\mathrm{kW}\) kettle and a \(1\,\mathrm{kW}\) toaster are switched on for the same time. Which transfers more energy?
  1. The \(2\,\mathrm{kW}\) kettle
  2. The \(1\,\mathrm{kW}\) toaster
  3. They transfer equal energy
  4. Neither transfers energy

Question 4

In a closed system, what happens to the total amount of energy?
  1. Stays constant
  2. Always decreases
  3. Always increases
  4. Becomes mass

Question 5

Which process transfers thermal energy most in a solid metal rod?
  1. Conduction
  2. Convection
  3. Evaporation
  4. Diffusion

Question 6

Which energy resource is non-renewable?
  1. Natural gas
  2. Wind
  3. Solar
  4. Tidal

Question 7

Why is loft insulation used in homes?
  1. To reduce the rate of energy transfer by heating
  2. To increase the home's energy output
  3. To make electricity directly
  4. To increase conduction through the roof

Question 8

When a bicycle slows because of braking, what is energy mainly transferred from?
  1. Kinetic store to thermal stores in brakes and surroundings
  2. Thermal store to kinetic store
  3. Chemical store to nuclear store
  4. Gravitational store to magnetic store

Question 9

What is meant by work done in physics?
  1. Energy transferred when a force moves an object through a distance
  2. Power used each second
  3. The total mass of an object
  4. Current flowing in a wire

Question 10

Why can simple machines let you use a smaller force?
  1. The force acts through a greater distance
  2. They create extra energy
  3. They remove all friction
  4. They reduce displacement to zero

Question 11

Which appliance uses the most energy in \(30\,\mathrm{min}\)?
  1. A \(1.8\,\mathrm{kW}\) hair dryer
  2. A \(600\,\mathrm{W}\) microwave
  3. A \(100\,\mathrm{W}\) phone charger
  4. A \(9\,\mathrm{W}\) LED lamp

Question 12

What does a kilowatt-hour (kWh) measure?
  1. Energy transferred
  2. Power
  3. Electric current
  4. Electrical charge

Question 13

A hot drink is left in a cool room. What happens over time?
  1. Thermal energy transfers to the room until temperatures become more similar
  2. The room transfers thermal energy to the drink until it gets hotter
  3. No energy transfer happens unless the drink is stirred
  4. The drink temperature stays fixed because energy is conserved

Question 14

Which action increases an object's gravitational potential energy store?
  1. Lifting it to a higher position
  2. Sliding it sideways at the same height
  3. Cooling it down
  4. Letting it fall

Question 15

What happens when fuel burns?
  1. Energy is transferred from a chemical store to other stores
  2. Energy is created from nothing
  3. Mass turns directly into electricity only
  4. No energy transfer occurs in combustion

Question 16

Which cup material is best for reducing energy transfer by heating from a hot drink?
  1. Polystyrene foam
  2. Copper
  3. Aluminium
  4. Steel

Question 17

In an ideal simple machine, what does using a smaller force usually mean?
  1. Applying that force over a longer distance
  2. Doing no work overall
  3. Creating extra energy in the machine
  4. Reducing the object mass

Question 18

How much energy does a \(1000\,\mathrm{W}\) kettle transfer in \(120\,\mathrm{s}\)?
  1. \(120000\,\mathrm{J}\)
  2. \(120\,\mathrm{J}\)
  3. \(1000\,\mathrm{J}\)
  4. \(12000\,\mathrm{J}\)

Question 19

A food label shows \(900\,\mathrm{kJ}\). What does this describe?
  1. The chemical energy available from the food
  2. The food's mass in kilograms
  3. The food's power rating in watts
  4. The food's temperature in degrees C

Question 20

Which statement describes a renewable energy resource?
  1. It can be replenished naturally as it is used
  2. It will definitely run out in one human lifetime
  3. It cannot be used for electricity generation
  4. It always has zero environmental impact

Question 21

A portable fan uses \(40\,\mathrm{W}\) of power for \(1800\,\mathrm{s}\). How much energy is transferred?
  1. \(72\,\mathrm{kJ}\)
  2. \(7.2\,\mathrm{kJ}\)
  3. \(720\,\mathrm{kJ}\)
  4. \(72000\,\mathrm{W}\)

Question 22

Which set lists only valid energy stores?
  1. Kinetic, thermal, and gravitational potential
  2. Voltage, force, and current
  3. Heat, work, and power
  4. Mass, charge, and resistance

Question 23

Which equation gives kinetic energy \(E_k\)?
  1. \(E_k = \tfrac{1}{2}mv^2\)
  2. \(E_k = mgh\)
  3. \(E_k = P t\)
  4. \(E_k = \tfrac{1}{2}k e^2\)

Question 24

If the speed of an object doubles and mass stays constant, what happens to its kinetic energy?
  1. Increases by a factor of \(4\)
  2. Increases by a factor of \(2\)
  3. Increases by a factor of \(8\)
  4. Stays the same

Question 25

Which equation links the change in thermal energy with mass, specific heat capacity and temperature change?
  1. \(\Delta E = mc\Delta \theta\)
  2. \(\Delta E = mL\)
  3. \(P = VI\)
  4. \(Q = It\)

Question 26

What is specific heat capacity?
  1. The energy needed to raise the temperature of \(1\,\mathrm{kg}\) of a substance by \(1\,^\circ\mathrm{C}\)
  2. The energy needed to melt \(1\,\mathrm{kg}\) of a substance at constant temperature
  3. The energy needed to increase the pressure of \(1\,\mathrm{m}^3\) of gas by \(1\,\mathrm{Pa}\)
  4. The energy needed to move \(1\,\mathrm{kg}\) at \(1\,\mathrm{m/s}\)

Question 27

Which equation defines power as the energy transferred per unit time?
  1. \(P = \frac{E}{t}\)
  2. \(P = Et\)
  3. \(P = \frac{V}{I}\)
  4. \(P = mgh\)

Question 28

A machine has \(200\,\mathrm{J}\) input and \(150\,\mathrm{J}\) useful output. What is its efficiency?
  1. \(75\%\)
  2. \(25\%\)
  3. \(133\%\)
  4. \(50\%\)

Question 29

How can unwanted energy transfer by heating from a hot pipe be reduced?
  1. Add thermal insulation around the pipe
  2. Increase the pipe temperature
  3. Use a thinner pipe wall
  4. Increase thermal conductivity

Question 30

Which equation gives energy transferred by electrical work using charge \(Q\) and potential difference \(V\)?
  1. \(E = QV\)
  2. \(E = IV\)
  3. \(E = \frac{Q}{I}\)
  4. \(E = \frac{V}{Q}\)

Question 31

In a closed system, what happens to energy that is dissipated?
  1. Still conserved but spread into less useful stores
  2. Destroyed completely
  3. Converted into mass only
  4. Removed from the system by definition

Question 32

Which equation links power \(P\), potential difference \(V\), and current \(I\)?
  1. \(P = VI\)
  2. \(P = \frac{V}{I}\)
  3. \(P = V + I\)
  4. \(P = I^2 R\)

Question 33

How much energy does a \(1.5\,\mathrm{kW}\) kettle transfer in \(4\,\mathrm{min}\)?
  1. \(360000\,\mathrm{J}\)
  2. \(600\,\mathrm{J}\)
  3. \(1500\,\mathrm{J}\)
  4. \(2500\,\mathrm{J}\)

Question 34

Charge of \(5\,\mathrm{C}\) passes through a potential difference of \(12\,\mathrm{V}\). How much energy is transferred?
  1. \(60\,\mathrm{J}\)
  2. \(0.42\,\mathrm{J}\)
  3. \(5\,\mathrm{J}\)
  4. \(60\,\mathrm{kJ}\)

Question 35

Which formula defines efficiency?
  1. \(\text{efficiency} = \frac{\text{useful energy output}}{\text{total energy input}}\)
  2. \(\text{efficiency} = \frac{\text{total input}}{\text{useful output}}\)
  3. \(\text{efficiency} = \text{power} \times \text{time}\)
  4. \(\text{efficiency} = \text{voltage} \times \text{current}\)

Question 36

A device has \(500\,\mathrm{J}\) input and \(200\,\mathrm{J}\) useful output. What is its efficiency?
  1. \(40\%\)
  2. \(25\%\)
  3. \(125\%\)
  4. \(60\%\)

Question 37

Why do power stations use step-up transformers on the National Grid?
  1. To raise voltage and reduce energy lost as heat
  2. To lower voltage for cheaper meters
  3. To make electricity direct current
  4. To store energy in the wires

Question 38

Which energy resource is renewable?
  1. Wind
  2. Oil
  3. Coal
  4. Natural gas

Question 39

What does a solar panel do?
  1. Converts light energy to electrical energy
  2. Converts thermal energy to chemical energy
  3. Blocks radiation from the Sun
  4. Stores gravitational energy

Question 40

Which equation gives gravitational potential energy \(E_p\)?
  1. \(E_p = mgh\)
  2. \(E_p = \frac{mg}{h}\)
  3. \(E_p = mg + h\)
  4. \(E_p = m^2 g^2\)

Question 41

A pump lifts \(15\,\mathrm{kg}\) of water \(4\,\mathrm{m}\). How much gravitational potential energy is gained if \(g = 10\)?
  1. \(600\,\mathrm{J}\)
  2. \(60\,\mathrm{J}\)
  3. \(1500\,\mathrm{J}\)
  4. \(15\,\mathrm{J}\)

Question 42

When energy is transferred electrically, which equation links charge and potential difference?
  1. \(E = QV\)
  2. \(E = \frac{Q}{V}\)
  3. \(E = V + Q\)
  4. \(E = Q/V\)

Question 43

Which energy store increases when a charged capacitor is connected to a battery?
  1. Electrical potential energy store
  2. Kinetic store
  3. Gravitational store
  4. Magnetic store

Question 44

Why are renewables with high capacity factors important for grid stability?
  1. They provide predictable output so other plants need to adjust less
  2. They always generate more than demand
  3. They require no maintenance
  4. They are immune to weather

Question 45

An energy audit shows \(2000\,\mathrm{J}\) input and \(1800\,\mathrm{J}\) useful output. Which statement follows?
  1. \(200\,\mathrm{J}\) is wasted, efficiency \(90\%\)
  2. Loss is \(2000\,\mathrm{J}\)
  3. Efficiency is \(180\%\)
  4. Useful output equals zero

Question 46

Which power rating transfers \(3000\,\mathrm{J}\) in \(10\,\mathrm{s}\)?
  1. \(300\,\mathrm{W}\)
  2. \(30\,\mathrm{W}\)
  3. \(3000\,\mathrm{W}\)
  4. \(0.3\,\mathrm{W}\)

Question 47

An electric lift needs \(5.0\,\mathrm{MJ}\) of electrical energy but only \(3.2\,\mathrm{MJ}\) becomes useful work. What is its efficiency?
  1. \(64\%\)
  2. \(36\%\)
  3. \(160\%\)
  4. \(82\%\)

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Review Energy questions for Physics, with correct answers shown and coverage across energy stores and transfers; conservation of energy; efficiency and power.

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