Magnetic Fields and Induction Quiz

What is the direction of the magnetic field around a current-carrying straight conductor?

• From north to south

• Clockwise when viewed from above if current flows downward

• Anticlockwise when viewed from above if current flows downward

• From negative to positive terminal

The magnetic field inside a solenoid is:

• Zero

• Strong and uniform

• Weak and random

• Strong and non-uniform

Which rule is used to determine the direction of the magnetic field inside and around a current-carrying solenoid?

• Fleming’s Left-hand Rule

• Right-hand Solenoid Rule

• Lenz’s Law

• Ohm’s Law

Which of the following will increase the strength of the magnetic field in a solenoid?

• Decreasing the current

• Using fewer coils

• Inserting a soft iron core

• Removing the battery

According to Faraday’s Law, the induced emf in a coil is:

• Directly proportional to the resistance

• Directly proportional to the magnetic flux

• Directly proportional to the rate of change of magnetic flux

• Inversely proportional to current

Which of the following does not affect the magnitude of the induced emf?

• Number of turns in the coil

• Speed of the magnetic field change

• Strength of the magnetic field

• Mass of the coil

Which of the following best explains why an emf is induced when a conductor moves through a magnetic field?

• A magnetic force acts on stationary charges

• Moving charges experience a force due to the magnetic field

• Magnetic fields only affect permanent magnets

• Magnetic fields cause heating in the wire

In electromagnetic induction, which combination of actions will increase the magnitude of the induced current in a coil?

• Use fewer coils and move the magnet slowly

• Use a weaker magnet and keep the coil stationary

• Use more coils and move the magnet faster

• Keep the number of coils the same and rotate the magnet slowly

Why must a transformer operate with alternating current (AC) rather than direct current (DC)?

• AC increases the resistance in the coils

• DC produces a stronger magnetic field than AC

• AC allows the magnetic field to continuously change and induce emf

• DC causes current to flow in both directions

The main purpose of the soft iron core in a transformer is to:

• Increase the resistance in the coils

• Reduce energy losses due to heat

• Strengthen the magnetic field and link it between coils

• Prevent magnetic field lines from spreading out