Worksheet on Static Electricity

Points to keep in mind:a. Conductors cannot have static electricity. Static electricity needs an insulatorb. When materials are rubbed against each other, electric charges are not created but only transfers

electrons from one object to the other.c. Electrons move from high potential to low potential (i.e from high number to low number)d. A neutral object can be charged by ‘induction’

1. Draw appropriate charges on each material and show the transfer of charges after rubbing.

Balloon and cloth before rubbing Balloon and cloth after rubbing

2. What happens if the balloon in stage 2 of Question 1 is in contact with a metal strip? Explain.

3. Why a PC monitor is covered with dust?

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4. After gaining electrons from the cloth, can the polythene rod attract small pieces of paper? Explain.

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BalloonCloth

Balloon

Cloth

Balloon

Metal

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5. Figure shows a copper rod and a piece of cloth. What happens when you rub the rod with the cloth? Explain your answer.

6. Figure shows two polythene rods under two different situations. Write which pair attracts and which pair repels.

7. When you walk across a nylon carpet, you become negatively charged. When you touch a metal handle you receive a shock. Explain why this happens.

8. Figure shows objects with charges. Show from which object the electrons flows. State why.

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Copper rod

Cloth

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(a)

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(b)

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i (a) ii

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-----+

i (b) ii

---+++

+-----

i (c) ii

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i (d) ii

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9. Figure shows 2 neutral objects.

a) Draw the induced charges on A and B when a positively charged object is brought near A.

b) What happens when A and B are separated and the positively charged object is also removed? Draw the charges on the figure.

c) Name this method of charging and explain.

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A B

A B

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A B