Chapter 16 - Electromagnetism

Question 1

What is a magnetic field?

Answer 1

A region surrounding a permanent magnet or electromagnet in which a moving charge would experience a force.

Question 2

What is magnetic flux?

Answer 2

The product of an area A and the component of B-field (flux density) perpendicular to the area A. (Wb)

Question 3

What are lines of flux?

Answer 3

Lines forming continuous loops from magnetic N-poles to magnetic S-poles - the lines indicate the direction of the vector B.

Question 4

What is magnetic flux density?

Answer 4

A measure of magnetic field strength - symbol B, unit tesla (T) or Wb m^-2

Question 5

What is a solenoid?

Answer 5

A long, current-carrying coil, which acts as an electromagnet.

Question 6

What is a weber?

Answer 6

Unit of magnetic flux - If the flux in a simple circuit of one coil changes at a rate of 1 Wb s^-1, an e.m.f. of 1V will be induced.

Question 7

Lines of flux will tend to…

Answer 7

… shorten and straighten. Straightening causes magnets to rotate and shortening causes them to be pulled together.

Question 8

What is flux linkage?

Answer 8

number of coils *