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Electricity and Magnetism: Practice Questions with Answers

Curriculum: Electricity And MagnetismGrades: 8–10Questions: 12Mode: Practice

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1. What is an electric current?

  1. A flow of electric charge through a material
  2. A measure of how hot a light bulb gets
  3. The force of gravity acting on a wire
  4. A type of magnet found only in nature
Show the answer
Answer: A. A flow of electric charge through a material
Electric current is the flow of electric charge, usually carried by moving electrons, through a conductor such as a wire.

2. Which of these materials is the best electrical conductor?

  1. Rubber
  2. Wood
  3. Glass
  4. Copper
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Answer: D. Copper
Copper is a metal whose outer electrons move freely, which lets electric charge flow through it easily, making it an excellent conductor.

3. What do we call a material that does NOT allow electric current to flow easily through it?

  1. A magnet
  2. A battery
  3. An insulator
  4. A conductor
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Answer: C. An insulator
An insulator is a material, like plastic or rubber, whose electrons are tightly held, so charge cannot flow through it easily.

4. What unit is used to measure electric current?

  1. Ampere
  2. Volt
  3. Watt
  4. Ohm
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Answer: A. Ampere
Electric current is measured in amperes (amps), which tell how much charge flows past a point each second.

5. In a simple circuit, what does a battery provide?

  1. Resistance that slows and stops the current flowing in the wires
  2. Magnetic force only, which pulls the charges from one end to the other
  3. Light without any current, which is then carried along to the bulb
  4. The energy that pushes electric charge around the circuit
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Answer: D. The energy that pushes electric charge around the circuit
A battery converts stored chemical energy into electrical energy, creating a voltage that pushes charges through the circuit.

6. What must a circuit have for electric current to flow continuously?

  1. A magnet placed nearby
  2. A closed, unbroken loop of conducting material
  3. A gap of open air in the wire
  4. Only a light bulb, nothing else
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Answer: B. A closed, unbroken loop of conducting material
Current needs a complete, closed path from one terminal of the power source, through the circuit, and back to the other terminal.

7. Two magnets are brought close together and they push each other away. What can you conclude?

  1. One of the magnets is not really magnetic
  2. The two poles facing each other are the same (both north or both south)
  3. Magnets never repel, only attract
  4. The two poles facing each other are opposite (one north, one south)
Show the answer
Answer: B. The two poles facing each other are the same (both north or both south)
Like magnetic poles (north-north or south-south) repel each other, which is why the magnets push apart.

8. What is a magnetic field?

  1. A field on a farm where the soil holds a large amount of iron ore and other metals
  2. The exact center point of a magnet, where all of its pulling power is kept inside
  3. A type of electric circuit that carries current from a battery to a small light bulb
  4. The region of space around a magnet where its magnetic force can be detected
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Answer: D. The region of space around a magnet where its magnetic force can be detected
A magnetic field is the invisible region surrounding a magnet where its force can push or pull on other magnetic materials.

9. What is an electromagnet?

  1. A magnet that only works underwater
  2. A magnet made only from a permanent bar of iron
  3. A battery connected to two magnets
  4. A coil of wire that becomes magnetic when electric current flows through it
Show the answer
Answer: D. A coil of wire that becomes magnetic when electric current flows through it
When electric current flows through a coiled wire, it creates a magnetic field, and wrapping the coil around an iron core makes the effect much stronger, forming an electromagnet.

10. Which everyday object relies mainly on static electricity, not current electricity?

  1. A toaster that heats bread when its metal coils glow bright red
  2. A cell phone charger plugged into a wall outlet during the night
  3. A flashlight that shines when its battery switch is turned on
  4. A balloon that sticks to a wall after being rubbed on hair
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Answer: D. A balloon that sticks to a wall after being rubbed on hair
Rubbing a balloon on hair transfers electrons, building up a static (stationary) electric charge that attracts it to a wall.

11. What happens to electrons when two different materials are rubbed together, like a balloon and hair?

  1. Protons jump from one material to the other, leaving one material with extra positive particles
  2. Electrons are destroyed by the friction, so both materials end up with less total electric charge than they had before
  3. Nothing happens to any particles, since rubbing only warms the surfaces without moving any charges
  4. Electrons can transfer from one material to the other, leaving one positively and one negatively charged
Show the answer
Answer: D. Electrons can transfer from one material to the other, leaving one positively and one negatively charged
Friction can knock loosely held electrons off one material onto the other, leaving the material that lost electrons positively charged and the one that gained them negatively charged.

12. Which of the following is a natural permanent magnet found in the Earth?

  1. Quartz (silica crystal)
  2. Lodestone (magnetite)
  3. Limestone (calcium carbonate)
  4. Cinnabar (mercury sulfide)
Show the answer
Answer: B. Lodestone (magnetite)
Lodestone is a naturally magnetized form of the mineral magnetite, and ancient people used it as one of the earliest known magnets.
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