Electromagnetism

A

100

Another name of solenoid

Inductor

200

I decide to change the following parameters through a solenoid:

1. I increase the number of turns

2. I fill a piece of iron through its core

But I keep the Current constant. What happens to the magnetic field?

Increases (It becomes stronger)

300

What is the difference between a solenoid and a simple electromagnet?

An electromagnet includes a solenoid along with a switch, and a battery. The solenoid is one of the electromagnet's components

400

Which hand rule do you use to find the direction of current or magnetic field through a solenoid?

And which fingers do you use to find their directions?

Right hand

Thumb = Magnetic field direction

Curled fingers = Current direction

B

100

A wire is between 2 magnets (S-N  wire  S-N), and a current passes through it. What happens to the wire?

A Force affects the wire

200

Hand rule will you use to find the direction of F when it is made by B and I?

Which fingers will you use to find the directions of I, B, and F?

Left-hand rule

B=index

I=middle

F=thumb

300

A 6 A current flows through a coil immersed in a Magnetic Field B=0.21 T. The total length of the coil is 1 m, but only 0.3 m are immersed into the magnetic field. Find the force made by this combination.

F=0.378 N

400

What is a commutator?

A component of the Electric Motor that cancels the current to prevent the motor stops spinning (DC Motors) or reverses the current (AC Motors).

C

100

Explain the hand rule involving the 3 quantities I, B,L when a Force and a Magnetic field make a current. 

Which hand is it?

I,B, F correspond to which fingers?

Right-hand rule

F= thumb

B= magnetic field

I=middle

200

What is my favourite color?

Green

300

Does a Generator converts Mechanical Energy to Electric Energy or vice versa?

Mechanical Energy to Electric Energy

400

Draw on the whiteboard the trend of Emf in function of time while a Generator spins, and explain why it is as it is.

Sinusoidal trend (sin(t))

Because by spinning the current changes direction

D

100

If you want a steady current flowing in a secondary solenoid, does the current in the primary have to be DC or AC?

AC

200

There is a coil on the right side, and a magnet on the left side, with the south pole toward the coil.

At a sudden, you remove the magnet away from the coil.

What is the direction of the magnetif field formed in the coil? (To the Left or Right?)

To the left

300

An ideal transformer has:

• Primary turns Np=500
• Secondary turns Ns=100N
• Secondary current Is=5 A

Find the primary current.

Ip = 1 A

400

In a "Step-down" transformer, the current:

a) is higher in the secondary than in the primary

b) is higher in the primary than in the secondary

c) does not change (same magnitude)

Correct choice:

a) is higher in the secondary than in the primary