Question

The potential difference between a pair of oppositely charged parallel plates is 393 V.

(a) If the spacing between the plates is tripled without altering the charge on the plates, what is the new potential difference between the plates?

(b) If the plate spacing is doubled while the potential difference between the plates is kept constant, what is the ratio of the final charge on one of the plates to the original charge

Answer 1

Accoridng to the given problem,

The charge is unchanged, so according to Guass law, the electricfield magnitude is unchanged.
a)The space is triple, so the potential diffirence V=E*d will be Triple, because E is the same. = 1179V.

b)The potential is constance and the distace is tdouble, it mean the electric field is reduced by 2 time.

V=E*d so E'/E=d/d'

so according to gauss law, the charges is also reduced by 2 times as well.

Ratio of charge finel/intial = 1/2.

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