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A spark passes though air when the poten...

A spark passes though air when the potential gradient is `3xx10^(6)` volts per metre what must be the radious of an isoated metal sphere which can be changed to a potentiial of 3 million voilts before there are sparks in the air?
`["Hint":E= (Q)/(4piepsi_(0)r^(2))and V=(Q)/(4piepsi_(o)r), thereforeE=(V)/(r)]`

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NN GHOSH-GAUSS THEOREM AND ITS APPLICATION-EXAMPLES(a)
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  6. An isolated metal sphere whose diameter is 10 cm has a potential of 8...

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  9. A metal plate of radius 20 cm is charged positively to a potential of ...

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  10. Two parallel plates which are 0.2 cm apart are raised to a potential d...

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  15. Calculate the elecric flux though a hemisphere of radius R . The elect...

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  16. Two point charges q and -q are separated by a distance 2l. Find the fl...

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  17. Show by the priciple of superpostion that is a cavity is removed from ...

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  18. A point changes 60nC is placed at the centre of a a thick , inssulated...

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  19. It has been experimentally observed that the electric field in a large...

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