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

Which set contains only energy stores?
  1. Kinetic, thermal, gravitational potential
  2. Kinetic, heat, gravitational potential
  3. Chemical, electrical, thermal
  4. Elastic potential, sound, nuclear

Question 2

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 3

Which equation gives a change in thermal energy?
  1. \(\Delta E = mc\Delta \theta\)
  2. \(\Delta E = mL\)
  3. \(P = VI\)
  4. \(Q = It\)

Question 4

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 5

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 6

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 7

In a closed system, dissipated energy is...
  1. Conserved but spread out
  2. Conserved in its original store
  3. Transferred outside the system
  4. Converted into useful work

Question 8

A moving car brakes to a stop. Which energy store increases?
  1. Thermal
  2. Kinetic
  3. Elastic potential
  4. Chemical

Question 9

A \(1.5\,\mathrm{kW}\) kettle runs for \(4\,\mathrm{s}\). How much energy is transferred?
  1. \(6\,\mathrm{kJ}\)
  2. \(0.375\,\mathrm{kJ}\)
  3. \(5.5\,\mathrm{kJ}\)
  4. \(6000\,\mathrm{kJ}\)

Question 10

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 11

Which expression gives elastic potential energy?
  1. \(\tfrac{1}{2}ke^2\)
  2. \(ke\)
  3. \(\tfrac{1}{2}mv^2\)
  4. \(mgh\)

Question 12

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

Question 13

Which conversion occurs in a photovoltaic panel?
  1. Light to electrical
  2. Thermal to electrical
  3. Electrical to light
  4. Chemical to electrical

Question 14

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 15

A \(150\,\mathrm{N}\) load rises \(4\,\mathrm{m}\). How much gravitational potential energy is gained?
  1. \(600\,\mathrm{J}\)
  2. \(37.5\,\mathrm{J}\)
  3. \(154\,\mathrm{J}\)
  4. \(6000\,\mathrm{J}\)

Question 16

A \(1\,\mathrm{kg}\) material with \(c=500\,\mathrm{J/(kg\,^{\circ}C)}\) warms by \(4\,^{\circ}C\). Energy gained?
  1. \(2000\,\mathrm{J}\)
  2. \(125\,\mathrm{J}\)
  3. \(504\,\mathrm{J}\)
  4. \(500\,\mathrm{J}\)

Question 17

How does lubrication reduce wasted energy in a machine?
  1. It reduces heating caused by friction
  2. It increases the machine's mass
  3. It raises the electrical resistance
  4. It stores more energy in gravity

Question 18

Why can wind power be less reliable than gas power?
  1. Its output depends on the weather
  2. Its fuel supply is finite
  3. Its output is constant
  4. Its generator produces direct current

Question 19

An audit records \(2000\,\mathrm{J}\) input and \(1800\,\mathrm{J}\) useful output. How much is wasted?
  1. \(200\,\mathrm{J}\)
  2. \(1800\,\mathrm{J}\)
  3. \(2000\,\mathrm{J}\)
  4. \(3800\,\mathrm{J}\)

Question 20

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 21

Which energy resource produces radioactive waste?
  1. Nuclear
  2. Wind
  3. Solar
  4. Tidal

Question 22

A \(2\,\mathrm{kg}\) object moves at \(3\,\mathrm{m/s}\). What is its kinetic energy?
  1. \(9\,\mathrm{J}\)
  2. \(6\,\mathrm{J}\)
  3. \(18\,\mathrm{J}\)
  4. \(4.5\,\mathrm{J}\)

Question 23

Which transfer lowers an electric motor's efficiency?
  1. Heating the surroundings
  2. Turning the output shaft
  3. Lifting the attached load
  4. Moving the vehicle

Question 24

Which station can begin supplying extra power fastest?
  1. Pumped storage
  2. Gas turbine
  3. Coal station
  4. Nuclear station

Question 25

During low demand, pumped storage increases which energy store?
  1. Gravitational potential
  2. Kinetic
  3. Chemical
  4. Thermal

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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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