Define principal focus of concave mirror.Where should we place a candle in front of a concave mirror to get an enlarged,erect im
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Answer:
Explanation:
The strength of the electric field produced by a charge Q is given by
where
Q is the charge
r is the distance from the charge
k is the Coulomb's constant
In this problem, the electric field that can be detected by the fish is
and the fish can detect the electric field at a distance of
Substituting these numbers into the equation and solving for Q, we find the amount of charge needed: