Q.10 Paheli had heard that rain water is as good as distilled water. So, she collected some rain water in a clean glass tumbler and tested it using a tester. To her surprise, she found that the compass needle showed deflection. What could be the reasons?

Rain water is the pure water which lacks impurities and dust particles. At this stage it can called as distilled water as it lacks conducting particles and ions.

The rain water behaves as an insulator until unless it gets mixed with air pollutants like sulphur dioxide, NO_x (different oxides of nitrogen) and dust particles which makes the rainwater acidic as well as a good conductor of electricity.

So, when Paheli tested the rainwater using a tester, the compass needle showed deflection..