What is LED?

When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

Name three liquids, which when tested in the manner shown in figure, may cause the magnetic needle to direct.

The bulb does not glow in the setup shown in figure. List the possible reasons. Explain your answer.

 

A tester is used to check the conduction of electricity through two liquids, labeled 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

Does pure water conduct electricity? If not, what can we do to make it conducting?

In case of fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.

A child staying in the coastal region tests the drinking water and also the seawater with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?

Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.

Paheli had heard that rainwater is as good as distilled water. So she collected some rainwater in a clean glass tumbler and tested it using a tester. To her surprise she found that the compass needle showed deflection. What could be the reasons?

Prepare a list of objects around you that are electroplated.