CBSE NCERT Solutions for Class 8 Science Chapter 14

Students are advised to stick to the NCERT solutions to make full use of their limited time and score optimum in exam. Going through the NCERT solutions will help to grasp all the fundamentals and clear the concepts in a very easy and effective way.

CBSE NCERT Solutions for Class 8 Science Chapter 14:

Question-1:

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
(i) liquid A is a better conductor than liquid B.
(ii) liquid B is a better conductor than liquid A.
(iii) both liquids are equally conducting.
(iv) conducting properties of liquid cannot be compared in this manner.

Solution:

(i) liquid A is a better conductor than liquid B.

Question-2:

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

Solution:

No. Pure water does not conduct electricity because it does not have free electrons
or ions to conduct electricity. Pure water can conduct electricity when a pinch of common salt is added to it, as salt Solution is conducting in nature.

Question-3:

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.

Solution:

Water may conduct electricity. If the electrical supply for the area is not shut off
and water is poured over electrical appliances, the electricity may pass through water and harm the firemen. That is why, in case of a fire, the firemen shut off the main electrical supply for the area before they use the water hoses.

Question-4:

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

Solution:

No, it is very risky and unsafe for the electrician to carry out electrical repairs
outdoors during heavy downpour because rain water contains dissolved salts. Therefore, rain water can conduct electricity. The electrician may get electrical shocks while working outdoors during rain.