Electricity Review

A student wants to increase the magnetic force between two bar magnets. What should the student do?

• Move the magnets farther apart.

• Move the magnets closer together.

• Make the positive poles face each other

• Make the negative poles face each other

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

A junkyard owner needs a device to locate and attract junkyard items made of iron. You recommend an electromagnet and provide him with an explanation for this choice.

• An electromagnet has a coil of wire which allows for one to locate iron.

• An electromagnet has an electric motor to give it more power to sustain the time needed to find the iron.

• An electromagnet has a magnetic force which allows one to locate the iron since the force attracts the metal.

• An electromagnet has a solenoid (wire coil) wrapped around an iron core which allows one to locate iron by attracting the metal.

Electrical wires sometimes have a plastic coating wrapped around them. How does his make the wires safer to handle?

• Plastic does not react chemically with air.

• Plastic is a good insulator.

• Plastic will melt if the wires overheat

A science lab has copper wire coated with rubber tubing, a plastic cup, and a pair of cotton gloves. Which of these materials is an electrical conductor?

• cotton gloves

• copper wire

• plastic cup

• rubber tubing

What is the main difference between a generator and a motor?

• Generator - electrical energy to mechanical energy Motor - mechanical energy to electrical energy

• a motor and generator only use electrical energy

• Generator - mechanical energy to electrical energy Motor - electrical energy to mechanical energy

• They are the same machine.

What must an object gain or lose to become electrically charged?

• protons

• electrons

• neutrons

• nucleus

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Markeisha needs to create an electromagnet for her science project. Which list of materials would best help Markeisha build her electromagnet?

• string, battery, metal nail

• battery, metal nail, wire

• glass rod, wire, battery

• glass rod, string, battery

What is the difference between a static charge and electric current?

• electric current builds up in one place

• Static charges build up in one place

• static chages flow from one place to another

• electric current jumps from one object to another

According to the electric field lines, how will these two objects move?

• They will move away from each other in the same direction because one is larger than the other

• They will move toward each other because the charges are the same

• They will move away from each other and in opposite directions because like charges repe

• They will move toward each other because like charges attract.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Why the child's hair stands up after he slides down the slide?

• Friction caused a transfer of electrons between the slide and the child, making each of his like-charged hairs repel each other.

• Energy was transferred from the slide to the child through induction, causing the child's hair to become charged and stand up.

• Energy was transferred from the child to the slide through conduction, causing the child's hair to become charged and stand up.

• Friction caused a transfer of electrons between the slide and the child, making his like-charged hairs attract the air through induction.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5