Permanent Magnets (1)

Question 1

Permanent magnets

Answer 1

• Bar

- Horseshoe

Question 2

Permanent magnets attract iron fillings to the ____ where the leakage fields occur.

Answer 2

ends where the leakage fields occur.

N and S

Question 3

Continuous magnetic lines of force flow -

Answer 3

from north to south

Question 4

Two types of magnetic fields used in MPI:

Answer 4

• Circular fields

- Longitudinal fields

Question 5

How are circular fields made?

Answer 5

They are the result of electrical current passed through the test material via a current carrying conductor.

Question 6

How are longitudinal fields made?

Answer 6

Produced indirectly through the use of a current carrying coil, electromagnetic or use of permanent magnets.

Question 7

What happens when circular and longitudinal fields are used in sequence?

Answer 7

To magnetize a part first in one direction, then the other to ensure detection of discontinuities.

Question 8

What happens when circular and longitudinal fields are used in rapid succession?

Answer 8

Where multi direction al magnetization equipment is used. strength of both the circular and longitudinal fields should be balanced.

Question 9

Units to measure strength of a magnetic field

Answer 9

CGS = Oersted

SI =A/m (H)

Question 10

How is a vector or resultant field made?

Answer 10

When a circular and longitudinal field are used together, but the intensity and timing differ.

Question 11

What is a Vector field?

Answer 11

a combined swinging field that has a direction and intensity that is different from other fields