Question

PLEASE HELP!!

The more coils in an electromagnet,

A. the weaker the magnetic force.
B. the stronger the electromagnet.
C. the greater the heat produced by the electromagnet.
D. the quicker the magnet will lose its magnetism when the current is turned off.

If a larger current passes through the coil of wire in an electromagnet, then

A. the magnetic field will be weaker.
B. more domains align in the magnet.
C. fewer domains align in the magnet.
D. the magnetic field remains the same.

When the current through an electromagnet ceases, what generally happens to the magnetic field?

A. The magnetic field stays the same.
B. The magnetic field eventually disappears.
C. The magnetic field eventually gets stronger.
D. The magnetic field eventually switches direction.

Answer 1

• One is C
• Two is B
• There is A

Step-by-step explanation:

In the last tutorial about Electromagnetism we saw that if we bend the conductor into a single loop the current will flow in opposite directions through the loop producing a clockwise field and an anticlockwise field next to each other. The Electromagnet uses this principal by having several individual loops magnetically joined together to produce a single coil.

Electromagnets are basically coils of wire which behave like bar magnets with a distinct north and south pole when an electrical current passes through the coil. The static magnetic field produced by each individual coil loop is summed with its neighbour with the combined magnetic field concentrated like the single wire loop we looked at in the last tutorial in the centre of the coil. The resultant static magnetic field with a north pole at

Answer 2

1. B

2. B

3. B

Step-by-step explanation:

The magnetic field produced by an electromagnet depends on the amount of current passing through the coils (I) and number of turns (n).

B= μ₀nI

1. Thus, if there are more coils in an electromagnet, the electromagnet would be stronger.Thus, option B is correct.

2. Also, if a larger current passes through the coil, more domains get aligned in the magnet and magnetic field becomes stronger. Thus, option B is correct.

3. When the current is stopped, the magnetic field of the electromagnet eventually disappears. ( I=0 ⇒B =0) Thus, option B is correct.