Electromagnets

What phenomenon occurs when electric currents produce their own magnetic fields?

• Thermodynamics

• Gravitation

• Electromagnetism

• Electrostatics

What rule helps to determine the direction of the magnetic field around a wire?

• Left hand rule

• Thumb rule

• Right hand rule

• Curl rule

What shape do the magnetic field lines around a straight wire carrying current take?

• Ellipses

• Concentric circles

• Straight lines

• Spirals

What is formed when you add many turns to a coil next to each other in one long piece of wire?

• A solenoid

• A transistor

• A capacitor

• A resistor

What is a key characteristic of the magnetic field within a solenoid?

• Weak and variable

• Strong and uniform

• Non-existent

• Weak and uniform

What can be used to massively increase the strength of an electromagnet's magnetic field?

• Adding a copper core

• Increasing the temperature

• Decreasing the current

• Adding an iron core

How can the direction of the magnetic field in an electromagnet be reversed?

• By adding a magnetic material

• By decreasing the number of turns in the coil

• By increasing the current

• By reversing the direction of the current

What happens to the magnetic field of an electromagnet when the power source is turned off?

• It disappears

• It reverses direction

• It remains unchanged

• It becomes permanent

Which of the following is NOT a way to increase an electromagnet's strength?

• Decrease the length of the coil

• Decrease the current

• Increase the number of turns in the coil

• Increase the current

What does the magnetic field outside the coil of a solenoid resemble?

• The field around a bar magnet

• The field around a charged particle

• The field around a non-magnetic material

• The field around a stationary electric charge