Question

when free end of a tester is dipped into a solution the magnetic needle show deflation

Answer 1

The deflection in the compass needle shows that current is flowing through the wounded wire and hence , through the circuit . The circuit is complete since free end of the tester are dipped in a solution . The solution is certainly a conducting solution .
This is the reason why the compass needle shows a deflection .
Hope it is helpful ....

Answer 2

Answer:

The deflection in the compass needle shows that current is flowing through the wounded wire and hence, through the circuit. The circuit is complete since free ends of the tester are dipped in a solution. The solution is certainly a conducting solution. This is the reason why the compass needle shows a deflection.