Unit 8.3 Quiz 3

 We can use ___________ to show the shape of a magnetic field. (Check all that apply.)

• a permanent magnet

• another magnet

• a compass

• iron filings

Answer explanation

A compass aligns with magnetic field lines, showing their direction, while iron filings visualize the shape of the field by aligning along the lines. A permanent magnet and another magnet do not directly illustrate the field shape.

Which of the following will NOT increase the strength of an electromagnet?

• adding an iron core inside the coils

• adding a bar magnet on the side

• adding batteries together

• winding more wire coils

Answer explanation

Adding a bar magnet on the side does not increase the strength of an electromagnet; it can interfere with the magnetic field. The other options enhance the electromagnet's strength by increasing current or magnetic material.

A bar magnet is suspended from a string free to rotate away from all magnetic material and other magnets. When the bar magnet comes to rest, the north pole of the magnet will be pointing:

• toward Earth’s North Pole.

• directly away from the center of Earth.

• toward the center of Earth.

• toward Earth’s South Pole.

Answer explanation

The north pole of a bar magnet is attracted to the Earth's magnetic north, which is actually a magnetic south pole. Therefore, when the magnet comes to rest, its north pole will point toward Earth’s North Pole.

The presence of a magnetic field may be detected by using a:

• light bulb

• compass

• small mass

• stationary charge

Answer explanation

A compass is sensitive to magnetic fields and aligns itself with the Earth's magnetic field, making it an effective tool for detecting the presence of a magnetic field. The other options do not respond to magnetic fields.

Tags

NGSS.MS-PS2-5

Which of the following has NO effect on the strength of the magnetic field around a current-carrying coil of wire?

• The number of turns of wire in the coil.

• The direction of the battery connected to the coil.

• The material of the core placed inside the coil.

• The amount of current flowing through the coil.

Answer explanation

The direction of the battery does not affect the strength of the magnetic field; it only determines the direction of the field. The number of turns, core material, and current all influence the field's strength.

Tags

NGSS.MS-PS2-3

When iron is added as a core to a current-carrying solenoid (coil of wire), the magnetic field strength of the solenoid increases because the:

• iron increases the current flowing around the coils of the solenoid.

• iron adds the strength of the Earth’s magnetic field to the solenoid.

• iron’s magnetic domains align with the field due to the current.

• iron is already magnetized.

Answer explanation

The correct choice is that iron’s magnetic domains align with the field due to the current. This alignment enhances the magnetic field strength of the solenoid, making it stronger than with just air or non-magnetic materials.

Tags

NGSS.HS-PS2-5

NGSS.HS-PS3-5

What would be the most accurate description of a magnetic pole?

• The part of a magnet that will interact most strongly with a ferromagnetic object.

• The parts of the magnet that are differently colored.

• The part of a magnet that attracts metal objects.

• The ends of a magnet.

Answer explanation

The correct choice describes a magnetic pole as the part of a magnet that interacts most strongly with ferromagnetic objects, highlighting its role in magnetic attraction, unlike the other options which are less precise.

Which of the following combinations are ALL ferromagnetic objects (are attracted to a magnet)?

• paper clip, magnetite, hematite, iron oxide

• magnesium, cobalt, iron, aluminum

• copper oxide, paper clip, magnetite, piece of cassette tape

• cobalt, nickel, iron, aluminum

• iron oxide, magnesium, copper, cesium

Answer explanation

The correct choice is 'paper clip, magnetite, hematite, iron oxide' as all these materials are ferromagnetic and will be attracted to a magnet. The other options include non-ferromagnetic materials like aluminum and magnesium.