Two identical insulated spheres, X and Y, suspended by threads from a ceiling, are
held at a small distance apart, as shown in the diagram below.
Sphere X carries a charge of + 4 x 10-18 C, while sphere Y has an excess of
30 electrons.
10.1 Calculate the magnitude of the charge on sphere Y. (3)
The spheres are now released and they move towards each other.
10.2 Give a reason why spheres X and Y move towards each other. (2)
The spheres are allowed to touch each other. After touching, they move away from
each other.
10.3 State the principle of conservation of charge in words. (2)
10.4 Calculate the charge on each sphere after they have separated. (4)
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