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Asked in GSEB Board July 2017 · Coulomb's law and superposition
Given: F=5 N; each charge doubled; distance halved.
Idea: Coulomb's law, F=(kq₁q₂)/(r²). The force is proportional to the product of the charges and to 1/(r²).
Charges: q₁q₂→(2q₁)(2q₂)=4q₁q₂, a factor of 4.
Distance: r→r/2, so r²→(r²)/4 and 1/(r²) grows by another factor of 4.
F'=4×4× F=16×5=80 N
So the new force is 80 N.
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