Electrostatics can be a nuisance but is also useful.

1. (a)A person walks across a carpet. As he touches a door handle he receives an electric shock. Suggest why this happens.[2]
2. (b)(i)In spray painting, small drops of paint with a positive charge emerge from a nozzle. The drops are used to paint the leg of a metal chair, which has a negative charge, as shown in Fig. 7. 1. Fig. 7.2 shows what happens when there is no charge on the nozzle, or on the drops or on the leg of the chair. [Figure 7.1] [Figure 7.2] The drops in Fig. 7.1 spread out more as they leave the nozzle than those in Fig. 7.2. Explain why.[2]
3. (b)(ii)Explain why the paint reaches the back of the leg in Fig. 7.1.[1]

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