Direction: Read the passage carefully and answer the following questions. Three specimens of magnetic material were tested using the apparatus shown in the diagram. When the switch is closed, the specimen picks up some of the iron nails but when the switch is opened, many or most of the nails fall off. The number of nails picked up and left on were found for three specimens. The table shows the results.
| Specimen |
Number of nails picked up |
Number of nails retained by the specimen |
| X |
35 |
4 |
| Y |
20 |
10 |
| Z |
40 |
3 |
What does the number of nails left on the material indicate ?
(A) Ability to retain magnetism when current is removed.
(B) Ability to induce e.m.f.
(C) To undergo magnetostriction on removal of current.
(D) Abitity to change strength of magnetic field
