Electrical and Magnetic Forces

Which of the following observations can be used to indicate the strength of the current created by the generator?

• The brightness of the bulb

• The mass of the generator

• The length of the handle

• The size of the magnet

Students removed a large magnet from an old speaker. The students held the magnet a few inches above some iron tacks, and they jumped up and attached to the magnet. When the students pulled the tacks off the magnet, some of them remained stuck to each other.

Which observation provides evidence that a magnetic force can act across a distance?

• Some of the tacks remained stuck together.

• The tacks the students used were made of iron.

• The magnet attracted tacks without touching them.

• The students got the magnet from an old speaker.

Tags

NGSS.MS-PS2-5

How do you increase the strength of electromagnets? 2 answers

• Decrease the number of loops of wire

• Increase the number of loops of wire

• Increase voltage or current

• Decrease voltage or current

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Which statement about magnetic poles is accurate?

• Same magnetic poles attract, while different magnetic poles repel.

• Same magnetic poles attract, while different magnetic poles attract.

• Opposite magnetic poles attract, while like magnetic poles repel.

• Opposite magnetic poles repel, while like magnetic poles attract.

What happens when the OPPOSITE poles of two magnets come near each other?

• The magnets push away.

• The magnets pull together.

• The magnets get bigger.

• The magnets disappear.

Tags

NGSS.MS-PS2-3

The space around a magnet where its force acts is called the:

• attract zone

• repel zone

• magnetic field

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Sarah is looking for a way to move her boat across the water without touching it directly. She included paperclips in the boat design so that the magnetic attraction between the paperclip and the magnet would pull the boat along the water's surface. Which statement is an accurate representation of what is happening with Sarah's boat?

• The attraction between the boat and the magnet pulls the boat toward the magnet.

• As Sarah gets further from the boat with her magnet, the attraction will decrease.

• The attraction between the boat and the magnet pushes the boat away from the magnet.

• The more paperclips that are attached to the boat, the stronger the force of attraction to the magnet.

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How is an electromagnet different from a bar magnet?

• Bar magnets have a north and south pole, but electromagnets do not.

• Electromagnets are strong, permanent magnets, but bar magnets are always weaker.

• Electromagnets are only magnetized when a current flows through a wire wrapped around the core.

• Bar magnets are attracted to ferromagnetic substances such as iron. Electromagnets are attracted to all metals.

Tags

NGSS.MS-PS2-3

When two magnets are attracting, the magnetic field lines are (a)  

• connecting

• not connecting

• half-connecting

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NGSS.MS-PS2-3

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A balloon has a negative charge. The glass rod has a positive charge. What will happen when the glass rod is brought near the balloon?

• The balloon will be attracted to the rod

• The balloon will be repelled by the rod

• The balloon will remain in place

• The balloon will spin in circles

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NGSS.MS-PS2-3

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