Electromagnetism.

Question 1

If the current is coming towards you, the field lines are…

Answer 1

Anticlockwise.

Question 2

What are the field lines like regarding a solenoid?

Answer 2

Outside of the coil of wire, the field lines look like the field lines around a bar magnet, with a clear north and south pole (remember that magnetic field lines around a magnet go from North to South). Inside, the field lines are parallel, uniform and strong.

Question 3

Fill in the blanks:
For both solenoids and straight wires, increasing the size of the current ______ the ________ of the magnetic field, and __________ the direction of the current flips the __________ of the magnetic field lines.

Answer 3

1) increases
2) strength
3) flipping
4) direction

Question 4

How would one make an electromagnet?

Answer 4

Wrap an insulated copper wire tightly around an iron screw or nail, taking care to form as many spirals as possible to create the best current. You can use your fingers to push the loops closer together. Continue wrapping and pushing the wire until you get to the end of the iron. You can then connect the wire to a battery, and create a circuit. This will allow the current to pass through the wire.

Question 5

Why are electrons important?

Answer 5

Electrons are repelled by the negative terminal and attracted to the positive terminal. The movement of electrons leads to a magnetic field, because the magnets contain domains and those contain electrons.

Question 6

Define a “solenoid”.

Answer 6

A solenoid is device comprised a coil of wire, sometimes with a core that is usually made of a magnetic material. It can be used to enhance magnetic strength.

Question 7

How can you adjust the strength of a solenoid?

Answer 7

1) Change the number of coils.
2) Increase the metal.
3) Switch out the core for something with stronger magnetism.

Question 8

What are the advantages of EMs?

Answer 8

They can be turned on and off, and the strength can be adjusted.

Question 9

Explain Michael Faraday’s discovery.

Answer 9

Any time a current flows in a wire, a magnetic field is generated around it. It there is a break in the circuit, then the current cannot flow all the way around,
meaning there will be no magnetic field. No flowing current = no magnetic field. This physical
phenomenon was discovered by Michael Faraday in 1830. This led to electricity and life today.

Question 10

What can you use a solenoid for?

Answer 10

Getting pieces of metal out of a patient’s eye.

Question 11

What is the formula for charge?

Answer 11

Q = IT.