Electric and Magnetic Forces Review

What is the term for a material that does not allow electric current to flow through it easily?

• Conductor

• Insulator

Answer explanation

An insulator is a material that resists the flow of electric current, making it difficult for electricity to pass through. In contrast, a conductor allows electric current to flow easily. Therefore, the correct term is 'Insulator'.

The south ends of two magnets will _________ each other.

• repel

• attract

Answer explanation

The south ends of two magnets will repel each other because like poles repel. Therefore, the correct answer is 'repel'.

Tags

NGSS.MS-PS2-3

(True or False) An electromagnet is still a magnet when there is no current running through it.

• True

• False

Answer explanation

False. An electromagnet requires an electric current to generate a magnetic field. Without current, it does not exhibit magnetic properties.

If you place the North pole of a magnet next to the South pole of another magnet, they will:

• Attract

• Repel

• Do nothing

• Shatter

Answer explanation

When you place the North pole of one magnet next to the South pole of another, they will attract each other due to the fundamental magnetic principle that opposite poles attract.

Tags

NGSS.MS-PS2-3

What type of energy is electrons flowing through a wire?

• Electrical energy

• Chemical energy

• Kinetic energy

• Mechanical energy

Answer explanation

Electrons flowing through a wire represent electrical energy, as they create an electric current. This energy is harnessed for various applications, distinguishing it from chemical, kinetic, or mechanical energy.

Why does the top magnet appear to float above the bottom magnet?

• The magnets are made of different materials.

• The like poles repel each other.

• The opposite poles repel each other.

• The magnets have different gravitational pull.

Answer explanation

The top magnet appears to float because the like poles (e.g., north-north or south-south) repel each other. This repulsion creates a force that counteracts gravity, making the top magnet seem to float above the bottom magnet.

Tags

NGSS.MS-PS2-5

What will happen as an electron (-) gets closer to a proton (+)?

• The repulsion will be stronger.

• The attraction will be stronger.

• The attraction will be weaker.

• Nothing will happen to the electric field.

Answer explanation

As the electron approaches the proton, the attractive force between them increases due to the inverse square law of electrostatics. Therefore, the attraction will be stronger.

Tags

NGSS.MS-PS2-3

An area that deflects and traps harmful particles, and results from the interaction between Earth's magnetic field and solar winds is called...

• atmosphere

• ozone layer

• magnetic fields

• magnetosphere

Answer explanation

The magnetosphere is the region around Earth where its magnetic field interacts with solar winds, deflecting and trapping harmful particles. This makes it the correct answer, unlike the atmosphere or ozone layer.

A ball on a string is being repelled (pushed away) by the metal bar. What must be the **charge on the ball**?

• positive

• neutral

• negative

Answer explanation

The ball is being repelled by the metal bar, indicating that both have the same type of charge. Since the metal bar is typically negatively charged, the ball must be positively charged to experience repulsion.

Tags

NGSS.MS-PS2-3

The lines on this image are called...

• magnetic field lines

• iron fillings

• graphite lines

• none of these

Answer explanation

The lines in the image represent magnetic field lines, which visually depict the direction and strength of a magnetic field. The other options do not accurately describe these lines.

Tags

NGSS.MS-PS2-5