Forces Unit (Gravity, Electricity & Magnetism)

What is produced by a stream of electrons flowing through a wire that is coiled around an iron core?

• an atomic field

• a radiation field

• a magnetic field

• 
  a static field

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S8P5 a-c

Tristen and Jordan are each holding a bar magnet with opposite poles facing each other. They walk in opposite directions until they stop feeling their magnet pull towards the other one. What can they conclude about the distance between them when they stop feeling their magnets pull?

• They are outside the magnetic field of their magnets.

• The distance made the magnets' force stronger.

• 
  The magnetic fields are far enough apart to change direction.

• The magnetic field was weaker when they were close.

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S8P5 a-c

Mrs. Ryan investigating with magnets. The student uses a bar magnet, a plastic ruler, and a paper clip to perform her investigation. Mrs. Ryan places the bar magnet at different distances from the paper clip along the ruler and observes if the paper clip is attracted to the magnet. Her set up and results are shown. Which argument can the student make using the evidence in her table?

• Magnetism depends on the materials of the objects.

• Magnetic fields are strongest at the poles of the magnet.

• Magnetic fields exist between objects that are not in contact.

• Magnetism increases as the distance between objects increases. 

Answer explanation

The table shows that the paper clip was attracted to the magnet at a distance which supports the argument that objects do not have to be in contact for the magnetic fields to exist. 

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S8P5 a-c

AJ claims that magnetic fields exist between objects. Which arguments would support AJ's claim? Select all that apply.

• A bar magnet is able to attract a pile of iron filings.

• The south pole of a bar magnet is not attracted to a wood block.

• An electromagnet with a wooden core does not attract paper clips.

• A fridge magnet holds a piece of paper in place on the metal door.

• The north pole of a bar magnet repels the north pole of a second bar magnet.

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S8P5 a-c

Ava Leigh claims that Earth has a magnetic field. Which evidence would best support the her claim?

• The student creates a working circuit that illuminates a bulb using wire and a battery.

• The student turns in all directions with a compass and the needle always points north.

• The student receives a shock after walking across the carpet and touching a doorknob.

• 
  The student rolls a ball down a large hill and the ball comes to a complete stop at the bottom.

Tags

S8P5 a-c

Which drawing below represents the electric field surrounding two objects that have equal magnitude charges of the same polarity?

• 
• 
• 
• 

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S8P5 a-c

JeanCarlo is investigating the distribution of charge in objects using friction. JeanCarlo gently rubs a rubber balloon on the fur of his pet cat. When he pulls the balloon away from the cat's fur, the fur is attracted to the balloon. Which best explains why the fur becomes attracted to the balloon? 

• Rubbing the balloon along the cat transfers extra protons from the balloon to the cat.

• Rubbing the balloon along the cat creates extra protons that will stick to both the balloon and cat.

• Rubbing the balloon along the cat transfers extra electrons from the cat to the balloon.

• Rubbing the balloon along the cat creates extra electrons that will stick to both the balloon and cat.

Answer explanation

As the electrons are transferred from the cat to the balloon, the cat's fur becomes positively charged and the balloon becomes negatively charged. 

Tags

S8P5 a-c

Match each action with the charging method it demonstrates.

• Charging by Conduction

• touching a metal sphere with a positive aluminum plate

• Charging by Conduction

• moving a negatively charged rod near a metal sphere; touching a grounded sphere

• charging by Induction

• touching a metal sphere with a negatively charged rod

• Charging by Friction

• rubbing a balloon on hair

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S8P5 a-c

When combing one's hair, the comb becomes positively charged. What happens to the hair being combed?

• It stays uncharged.

• It becomes positively charged.

• It becomes negatively charged.

• It loses electrons.

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S8P5 a-c

Tyrone places a magnet at different distances from a pile of paper clips. He notices that the closer the magnet is, the more the paper clips are attracted to it. What can he conclude about the relationship between distance and the force of attraction between objects?

• The closer a magnet is to an object, the lesser the force of attraction.

• The closer a magnet is to an object, the greater the force of attraction.

• The farther a magnet is from an object, the greater the force of repulsion

• The farther a magnet is from an object, the greater the force of attraction.

Tags

S8P5 a-c