In some situations, even when the liquid is conducting, the bulb does not alone
What could be the reason?
Answers
This is because the electrons in the liquid are bound and and are not free to move. In liquid, due to interning forces, electrons are not very free and thus if they don't move, then there is no question of them being a conductor.
Answer:
An electric bulb glows due to the heating effect of electric current. This means the filament of bulb gets heated to a high temperature and it start growing. However if the current through a circuit is too weak the filament does not get heated sufficiently and it does not glow. The current in the circuit maybe week due to many reasons. For example a material may be slightly conduct it may not conduct electricity as easily as a metal. As a result the circuit to the testa maybe complete and get the current through it may be too weak to make the bulb glow. Also the voltage of battery used in the electric tester may be quite slow so that even a material is good conductor but the current produced is very weak in the circuit. This current may not be sufficient to glow the bulb.