MEDIUM
8th CBSE
IMPORTANT
Earn 100
Explain why, distilled water does not conduct electricity but tap water conducts some electricity.
Important Questions on Chemical Effects of Electric Current
MEDIUM
8th CBSE
IMPORTANT
Distilled water does not conduct electricity. What substances can be added to distilled water in small amounts to make it a good conductor of electricity? Why?
EASY
8th CBSE
IMPORTANT
Which of the two is a better conductor of electricity: drinking water (tap water) or sea water? Give reason for your answer.
MEDIUM
8th CBSE
IMPORTANT
Why does a brand-new bicycle have shining handle-bar and wheel rims? What will happen if these are accidentally scratched?
MEDIUM
8th CBSE
IMPORTANT
Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.
HARD
8th CBSE
IMPORTANT
When the free ends of a conductivity tester (made by using a battery connected to a wire wound around a compass) are dipped into a solution, the magnetic needle shows deflection. Can you give the reason for this deflection.
HARD
8th CBSE
IMPORTANT
A beaker contains an acidified copper sulphate solution. A copper plate and a carbon rod are kept in this copper sulphate solution. The copper plate is connected to the positive terminal of a battery whereas the carbon rod is connected to the negative terminal of the battery. What will you observe when an electric current is passed through this set-up for a considerable time?
MEDIUM
8th CBSE
IMPORTANT
Does pure water conduct electricity? If not, what can we do to make it conducting?
MEDIUM
8th CBSE
IMPORTANT
In case of a fire, before the firemen use the water hoses to throw water to douse fire, they shut off the electricity supply for the area. Explain why this is done.
