Electromagnetism

Question 0

What does a generator need to work/how does it work?

Answer 0

Motion, coil, magnet

1. Magnet near coil
2. Move one (either magnet or coil)
3. Change in magnetic field induces current

Question 1

Describe what a motor needs to work/how a motor works

Answer 1

Electricity (current), coil, magnet

1. Put magnet near coil
2. Current is in coil
3. Magnetic field is created
4. Magnet exerts force on magnetic field
5. Coil spins
6. Coil spins blades

Question 2

Describe now a transformer works

Answer 2

Needs primary and secondary circuits/coils
Alternating current in primary coil causes a change in magnetic field in the secondary coil, which either “steps up” or “steps down” voltage or current in the secondary coil, while power stays the same.

Question 3

What are the factors that increase the force that the magnet exerts on the wire?

Answer 3

1. If current increases, force increases
2. If distance decreases, force increases
3. If strength of magnetic field increases, force increases
4. If number of coils increases, force increases

Question 4

What are the factors that determine how much current is generated?

Answer 4

1. Speed of movement of magnet or coil increases, current increases
2. Strength of magnetic field increases, current increases
3. Number of coils increase, current increases
4. Distance decreases, current increases

Question 5

Why does dropping a magnet on the ground affect its magnetism?

Answer 5

Its domains misalign

Question 6

Why can’t a power company take a solenoid with millions of loops?

Answer 6

There would be too much opposing force (since magnetic fields oppose each other) and therefore it would take more force to create greater current

Question 7

Why does the power company transmit power at a high voltage?

Answer 7

High voltage = less current and less energy lost to heat, which saves money

Question 8

How do you make a magnet?

Answer 8

(It has to be magnetic, so cobalt, iron, nickel, or steel) and it must be put into a magnetic field so that the domains align

Question 9

What’s a domain?

Answer 9

Electrons that spin in the same direction

Question 10

What creates a magnetic field?

Answer 10

Current

Question 11

What causes a change in magnetic field?

Answer 11

Moving coil or magnet

Question 12

What must a particle be doing in order to experience a magnetic force? Must it be charged?

Answer 12

It must be moving and charged

Question 13

If you change the direction of current in the wire, what happens to the magnetic field?

Answer 13

Changes direction: arrows go the other way b/c poles switch