Electricity and Electromagnetism questions

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Electricity and Electromagnetism question collection

Review Electricity and Electromagnetism questions for Physics, with correct answers shown and coverage across defining electric current; choosing which unit is used to measure electric current; defining potential difference (voltage).

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Question 1

What is electric current?
  1. A flow of electric charge
  2. A build-up of stationary charge
  3. A transfer of thermal energy
  4. A force between magnetic poles

Question 2

Which unit is used to measure electric current?
  1. Ampere (A)
  2. Volt (V)
  3. Ohm (Ω)
  4. Joule (J)

Question 3

What is potential difference (voltage)?
  1. Energy transferred per unit charge
  2. The current lost per second
  3. The resistance of the wire
  4. The temperature of the source

Question 4

What does resistance describe?
  1. How much a component opposes the current
  2. How fast charges move past each other
  3. The number of electrons in the wire
  4. The brightness of a bulb

Question 5

How does current behave in a series circuit?
  1. Same at every point
  2. Lower after each component
  3. Divided equally between components
  4. Greatest beside the battery

Question 6

How does potential difference behave across parallel branches?
  1. Same across each branch
  2. Divided equally among the branches
  3. Lower across branches farther from the cell
  4. Greater across branches with lower resistance

Question 7

What happens to total resistance when resistors are added in series?
  1. It increases
  2. It decreases
  3. It stays unchanged
  4. It becomes the resistance of one resistor

Question 8

Which material is a good electrical conductor?
  1. Copper
  2. Plastic
  3. Glass
  4. Dry wood

Question 9

What does a fuse do?
  1. Melts if current exceeds its rating
  2. Carries fault current safely to earth
  3. Reduces the mains potential difference
  4. Switches off when an appliance overheats

Question 10

What is the role of an earth wire?
  1. Carry fault current safely to earth
  2. Supply current to the appliance
  3. Return normal current to the supply
  4. Melt when current exceeds a safe value

Question 11

In the UK, what colour is the live wire that carries ~\(230\,\mathrm{V}\)?
  1. Brown
  2. Blue
  3. Green
  4. White

Question 12

What happens when a switch is opened?
  1. The circuit breaks and current stops
  2. The switch bypasses the component
  3. A new parallel branch is connected
  4. The current reverses direction

Question 13

Which energy transfer occurs in a resistor?
  1. Electrical energy to thermal energy
  2. Electrical energy to chemical energy
  3. Thermal energy to gravitational energy
  4. Chemical energy to elastic energy

Question 14

Where is an ammeter placed to measure current through a component?
  1. In series with the component
  2. In parallel across the component
  3. Across the power supply
  4. Across an open switch

Question 15

Where is a voltmeter placed to measure a component?
  1. In parallel across the component
  2. In series before the component
  3. In series after the component
  4. Across the ammeter

Question 16

How can static electricity be produced?
  1. Transferring electrons by rubbing insulators
  2. Connecting conducting wires in parallel
  3. Heating a conductor until it glows
  4. Moving a magnet through a coil

Question 17

What do objects with the same type of charge do?
  1. They repel
  2. They attract
  3. They remain at a fixed distance
  4. They rotate without moving apart

Question 18

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

Question 19

At constant resistance, what happens to current when potential difference increases?
  1. It increases
  2. It decreases
  3. It stays unchanged
  4. It alternates direction

Question 20

Why are electrical wires covered with insulation?
  1. Prevent contact with the conductor
  2. Increase current through the conductor
  3. Carry fault current to earth
  4. Melt when current is excessive

Question 21

A torch uses a \(9\,\mathrm{V}\) battery and a \(3\,\mathrm{\Omega}\) bulb. What current flows?
  1. \(3\,\mathrm{A}\)
  2. \(0.33\,\mathrm{A}\)
  3. \(6\,\mathrm{A}\)
  4. \(9\,\mathrm{A}\)

Question 22

What is electrical charge measured in?
  1. Coulomb (C)
  2. Ampere (A)
  3. Ohm (Ω)
  4. Watt (W)

Question 23

How is supply potential difference divided across identical lamps in series?
  1. Equally between the lamps
  2. Entirely across the first lamp
  3. Full supply across each lamp
  4. According to distance from the cell

Question 24

Why are parallel circuits useful in homes?
  1. Each branch can work independently
  2. One switch must control every branch
  3. Supply voltage is shared between branches
  4. Adding one branch stops the others

Question 25

Which component is used to change resistance as light level changes?
  1. LDR
  2. Diode
  3. Fuse
  4. Cell

Question 26

What happens to resistance in a filament lamp as it heats up?
  1. It increases
  2. It stays constant as temperature rises
  3. It decreases as temperature rises
  4. It depends only on battery voltage

Question 27

Which equation links electrical energy, power and time?
  1. (E = Pt)
  2. (E = P/t)
  3. (E = P+t)
  4. (E = t/P)

Question 28

A \(60\,\mathrm{W}\) lamp is used for \(10\,\mathrm{s}\). How much energy is transferred?
  1. \(600\,\mathrm{J}\)
  2. \(6\,\mathrm{J}\)
  3. \(60\,\mathrm{J}\)
  4. \(6000\,\mathrm{J}\)

Question 29

Why must a fuse have the correct rating?
  1. It melts when current exceeds a safe value
  2. It melts during the normal operating current
  3. It raises the current supplied to the appliance
  4. It carries fault current safely to earth

Question 30

What does an LED do in a circuit?
  1. It emits light when current flows in the forward direction
  2. It emits light when current flows in either direction
  3. It stores charge when current stops flowing
  4. It measures current when connected in series

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Review Electricity and Electromagnetism questions for Physics, with correct answers shown and coverage across defining electric current; choosing which unit is used to measure electric current; defining potential difference (voltage).

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