Four metal rods are placed, in turn, inside a coil of copper wire,
The table below gives the results of the experiment. Which rod would be the most suitable to use for the case of a coil in a circuit breaker?
| Metal rod |
Number of paper clips picket up when there is a current in the coil |
Number of paper clips still attracted when the current is switched off |
| (a) |
1 |
0 |
| (b) |
20 |
2 |
| (c) |
35 |
0 |
| (d) |
35 |
30 |
A. (a) B. (b) C. (c) D. (d)
