Q.7 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.

In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. This is because the water contains various minerals and ions which are conducting particles.

As water may conduct electricity and in case of leakage if the water is poured over the working electrical appliances then the electric current may pass through the water to everyone in contact with water and thus can harm the firemen.