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GCSE Questions: Static Electricity

Q10. A charged rod is brought towards a gentle stream of water from a tap.

(a) Explain how the charged rod affects the stream of water.

The rod attracts water stream towards it and the water stream bends (or moves towards) the rod .

Opposite charges attract, and as water molecules are polar (the oxygen end of the molecule is more negatively charged that the end that has the hydrogen atoms - see above) whatever the static charge on the rod the water stream will be attracted towards the rod, as the oppositely charged part of the molecule will be attracted toward the rod.

[3 marks]

(b)

(i) Write down the conditions needed for charge to flow through a conductor.

A potential difference across the conductor

It needs to be within a closed or complete circuit

[2 marks]

(ii) Calculate the charge that flows past a point in a circuit with a 5.0 A current for five minutes.

I = Q/t

Q = It

t = 5 minutes = 5 x 60 = 300 s

Q = 5 x 300 = 1500 C

[4 marks]

[Total 9 marks]