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basic electrostatics
electrostatics for third form revision
Question | Answer |
---|---|
Name the two kinds of electric charge. | Positive and negative. |
What kind of charge do electrons have? | negative. |
What do charges that are the same do to each other? | repel |
What do charges that are different do to each other? | attract |
A cloth rubs a balloon. The balloon becomes negative. What has moved, and which way? | electrons, from the cloth onto the balloon. |
A positively charged plastic rod is discharged by being connected to Earth. What has moved, and which way? | electrons, from Earth onto the rod. |
A paint gun is charged and the paint drops spread in fine mist. Why? | They all have the same charge and repel each other. |
Paint from a charged up paint gun spreads evenly round a metal bike frame. Why? | It has the opposite charge and like charges attract. |
A fuel tanker is always 'earthed' before petrol is unloaded from it. Why? | Friction between tyres and road, or fuel and pipes, can cause electric charge to build up. This could cause spark and explosion. |
Why do helicopters get charged up as they fly through the air? | friction between rotors and air causes rotors to become charged. |