5. Exercise V

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  

• Yes, pure water partially conducts electricity.
• No, pure water doesn’t conduct electricity.
• Yes, pure water conducts electricity.
• No, pure water partially conducts electricity.

 

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.

  

The water in the water hoses is purenot pure and is a good conductor of electricitybad conductor of electricity. To protect themselves and others from electrocution, the firemen turned off the power before spraying water.