Electromagnetic Force Assessment

What happens when two north poles of magnets are brought close together?

• They attract each other
• They repel each other
• They become stronger
• They become weaker

Which of the following is a characteristic of a permanent magnet?

• It loses magnetism when the magnetic field disappears
• It exhibits magnetic properties almost all the time
• It requires electricity to function
• It only works in the presence of another magnet

What is an electromagnet?

• A permanent magnet with constant strength
• A temporary magnet created when there is a current in a wire or coil
• A magnet that only works in the absence of electricity
• A natural magnet found in the earth

How can you increase the strength of a magnetic field produced by a solenoid?

• Decrease the number of coils
• Increase the number of coils
• Use a non-metal core
• Use a larger battery

What do magnetic field lines represent?

• The force of gravity
• Lines of force caused by electric fields
• Directions of force in a magnetic field
• The strength of the earth's rotation

What happens when a south pole and a north pole of magnets are brought together?

• They repel each other
• They attract each other
• They become neutral
• They rotate

Which of the following describes Earth's magnetic field?

• It only affects electronic devices
• It has no effect on compasses
• It has a north and south magnetic pole
• It is the same as the geographic poles

What determines the strength of electromagnetic force?

• The shape of the magnet
• The temperature of the magnet
• The magnitude of charge and distance
• The size of the magnet

What is one key difference between static electricity and current electricity?

• Static electricity is moving, while current electricity is not
• Static electricity involves a flow of electrons, while current electricity does not
• Static electricity is not moving, while current electricity is moving
• Static electricity is always stronger than current electricity

What is the primary purpose of an electromagnet in a motor?

• To convert mechanical energy into electrical energy
• To convert electrical energy into mechanical energy
• To maintain a constant magnetic field
• To decrease the efficiency of the motor