# Isaac Physics question - Help!

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#1
1) A metal sphere with a radius of 7.4cm is at a potential of 1.8MV. Calculate the charge stored on the sphere.
I got answer 1.5x10^-5 C which is correct.

I was stuck on second part:
2) Calculate the potential of a point 13.6cm from the centre of the sphere in H9.7.
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1 year ago
#2
(Original post by Rupert945)
1) A metal sphere with a radius of 7.4cm is at a potential of 1.8MV. Calculate the charge stored on the sphere.
I got answer 1.5x10^-5 C which is correct.

I was stuck on second part:
2) Calculate the potential of a point 13.6cm from the centre of the sphere in H9.7.
1. Q = 1.8 x 10^6 x 4 pi x 8.85 x10^-12 x 7.4 x 10^-2 = 1.5 x 10^-5 C

2.
hence V = 1.5 x 10^-5 C /( 4 pi x 8.85 x 10^-12 x 13.6 x 10^-2) = 9.79 x 10^5 V

ALTERNATIVE:
1.8 x 7.4 = 13.6 x V
so V = 0.979 MV
1
#3
Thanks !!
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