Students, you may need to practice a lot while preparing for CBSE board exams and other exams. These sets of important questions in science will help you in dealing with difficult topics too. Download free pdf for practise.
Important questions based on NCERT syllabus for Chapter 12 - Electricity and Circuits:
Question-1: Is distilled water a conductor of electricity? Give reasons for your answer.
Solution: No, the distilled water is the purest form of water and it acts as an insulator. Therefore it is used in batteries as an insulator. For conduction of electricity, water should have dissolved ions in it but distilled water does not have any ions for conduction of electricity. To conduct electricity through distilled water, we need to add some impurities such as salts. The tap water, sea water contains some traces of salts and impurities, due to which it becomes good conductor of electricity.
Question-2: Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.
Solution: Since electricians work on electric devices or circuits which may contain live wires (wires carrying current) and they may accidentally come in contact with them. Since human body is also a good conductor, electricians may get shock. Rubber is a good insulator. To prevent themselves from electric shock or flow of current, the electricians use rubber gloves while repairing.
Question-3: Conductors and insulators both are equally important. Explain why?
Solution: The material, which conducts electricity, is known as conductor. In day to day life, we use so many electrical appliances which are made up of conductors. These conductors help us to create an electrical path for the electricity to flow through it. Hence, conductors play an important role in day to day life. Since direct contact with electrical circuits can be fatal as electric current can give fatal burns. So to protect ourselves from electricity, we can use insulators which acts as a protecting layer as insulators do not conduct electricity. Hence, both conductors and insulators are equally important in day to day life.