Chapter 2 Test Study Guide

What type of material should be used for the wire in an electromagnet to achieve the highest magnetic field?

• copper

• glass

• plastic

• rubber

Tags

NGSS.MS-PS2-3

How can we most effectively provide evidence for the existence of magnetic fields?

• by monitoring the speed of a moving object

• by analyzing the light absorption of a material

• by investigating the insulating properties of different materials

• by observing the attraction between a magnet and magnetic materials

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

What is the impact on an electric motor when the strength of its magnetic field is decreased?

• The motor's speed decreases.

• The motor's speed increases.

• The motor's direction of rotation changes.

• No change is observed in the motor's operation.

Tags

NGSS.MS-PS2-5

What is the relationship between the number of coils in an electromagnet and its electric current?

• The number of coils does not affect the electric current.

• Increasing the number of coils reduces the electric current.

• Increasing the number of coils increases the electric current.

• Increasing the number of coils changes the direction of the current.

A generator is made by a student using a disc, ball bearings, a motor, copper wire, and an LED bulb, as shown.

When the shaft rotates the disc at the rate of 30 rotations per minute, the LED glows dimly. However, if the shaft is rotated 60 rotations per minute, the LED glows brightly. What can be concluded from this experiment?

• By increasing the number of rotations of the disc, the induced current in the wire decreases, and the LED glows dimly.

• By decreasing the number of rotations of the disc, the induced current in the wire increases, and the LED glows dimly.

• By increasing the number of rotations of the disc, the induced current in the wire increases, and the LED glows brightly.

• By decreasing the number of rotations of the disc, the induced current in the wire increases, and the LED glows brightly.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

How does the magnetic field of an electromagnet change when the current flowing through its coils is increased?

• The magnetic field decreases.

• The magnetic field strengthens.

• The magnetic field changes direction.

• The magnetic field remains unchanged.

Tags

NGSS.MS-PS2-3

A student makes two electromagnets by coiling the iron nail with wire and joining the wire to the battery, as shown.

In the first electromagnet copper wire is used, while in the second electromagnet, silver wire is used. Then, the student keeps some metal paper clips near the iron nail and observes the number of paper clips getting attracted to the nail in both electromagnets.

Which two conclusions can be drawn from the experiment?

• The strength of the electromagnet is dependent on the insulation material of the wire used.

• The strength of the electromagnet is dependent on the number of turns of wire around the nail.

• The strength of the electromagnet is independent of the number of turns of wire around the nail.

• The strength of the electromagnet is dependent on the material of wire used and its electrical conductivity.

• The strength of the electromagnet is independent of the material of wire used and its electrical conductivity.

A student designs three conducting coils and passes them across a magnetic field to observe the induced current in them one after the other.

If coil 1 has one turn, coil 2 has two turns, and coil 3 has three turns, then which two statements are correct?

• The current across coil 3 is the largest.

• The current across coil 1 is the largest.

• The current across coil 1 is twice as large as that across coil 2.

• The current across coil 3 is three times larger than that across coil 2.

• The current across coil 3 is three times larger than that across coil 1.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

In building an optimal generator, what factor could potentially elevate the generated electricity?

• changing the wire's color

• the size of the generator coils

• the pattern drawn on the casing

• intensifying the magnet's strength

A student makes an electromagnet by coiling the iron nail with copper wire and joining the wire to the battery, as shown.

Then, the student keeps some metal paper clips near the iron nail, varies the strength of the battery used, and notes how many paper clips get attracted to the nail.

What can be concluded about the strength of the electromagnet when varying the strength of the battery?

• The higher the voltage of the battery, the less the current flows through the wire, leading to a weaker electromagnet.

• The lower the voltage of the battery, the less the current flows through the wire, leading to a stronger electromagnet.

• The higher the voltage of the battery, the more the current flows through the wire, leading to a stronger electromagnet.

• The higher the voltage of the battery, the more the current flows through the wire, leading to a weaker electromagnet.

Tags

NGSS.MS-PS2-3