Unit 7 Lessons 3, 4, & 5 Quiz Review

Mr. Smith warned his students not to have hair dryers plugged in near a bathtub full of water because of the risk of electric shock. What type of material is water?

• An insulator that does not allow charges to move easily
• A conductor that allows charges to move easily
• A semiconductor that can be used to control the flow of a charge
• A discharge that rapidly loses charge

The strength of an electric field around two charged objects depends on the amount of charge of each object and

• the distance between the objects
• the gravitational pull of the objects
• the mass of the two objects
• the polarity of the two objects

This image shows three pairs of circular objects.  Which statement is true about the top two pairs?

• The objects in these pairs are moving away from each other because like charges repel.
• The objects in these pairs are moving toward each other because like charges repel.
• The objects in these pairs are moving away from each other because like charges attract.
• The objects in these pairs are moving away from each other because unlike charges repel.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

The principle of conservation of charge states that:

• Electrons can be destroyed in order to change charges.
• Only negatively charged objects have any electrons.
• Charging objects involves moving electrons from one object to another.
• Electrons can be created in order to change charges.

How do we know that the Earth's geographic north pole is actually the Earth's magnetic south pole?

• Compass magnets' north pole points to the geographic north pole, so that must be the magnetic south pole.
• Compass magnets can't help us understand Earth's magnetic poles at all.
• The geographic north pole is the same as the magnetic north pole, no matter what compass magnets say.
• Compass magnets can only work in the western hemisphere.

What is the definition of a domain?

• An iron core wrapped inside of a solenoid
• A push or a pull created by two magnets
• An non-magnetic material such as plastic
• Groups of atoms that have aligned north and south poles

A magnetic field is a region around a magnet in which you can measure magnetic forces.  At which part(s) of the magnet is the magnetic field strongest?

• The poles
• The middle
• The horseshoe bend
• Any part covered in plastic

Industrial electromagnets are useful for picking up some heavy objects.  What would objects have to be made of to be attracted to an electromagnet?

• Plastic
• Silicon
• Iron
• Rubber

Which of the following devices uses a simple magnet?

• galvanometer
• handheld compass
• electric motor
• ear bud

An electric buzzer uses an electromagnet to make a loud repetitive sound. A coil of wire is wrapped around a bolt, which is magnetized.  It attracts the nail, which moves away from the pop can and breaks the circuit.  The nail then snaps back and hits the pop can, making noise. Which statement is true?

• When electric current runs through the coil of wire, a magnetic field is generated.
• This system shows a transfer of electricity, but not magnetism.
• Coils of wire are not usually attracted to magnets.
• Currents always cause magnets to gain power.