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 rodNumber of paper clips picket up when there is a current in the coilNumber of paper clips still attracted when the current is switched off(a)10(b)202(c)350(d)3530A. (a) B. (b) C. (c) D. (d)

Four metal rods are placed, in turn, inside a coil of copper wire,The

1.	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 rodNumber of paper clips picket up when there is a current in the coilNumber of paper clips still attracted when the current is switched off(a)10(b)202(c)350(d)3530A. (a) B. (b) C. (c) D. (d)
Answer» The core of solenoid must be of some soft type magnetic material which can be strongly magnetized but does not retain induced magnetism.