List of top Science Questions on Chemical Effects of Electric Current asked in CBSE Class VIII

The bulb does not glow in the setup shown in Fig.11.10. List the possible reasons. Explain your answer.
bulb setup
When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?
In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.
A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dimly for liquid B. You would conclude that
Name three liquids, which when tested in the manner shown in Fig.11.9, may cause the magnetic needle to deflect.
Fig.11.9