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COMEDK2016PhysicsElectrostatics

Distance between the two point charges is increased by 20 % . Force of interaction between the charges

Options

  1. Aincreases by 10 %
  2. Bdecreases by 20 %
  3. Cdecreases by 17 %
  4. Ddecreases by 31 %

Correct answer

D. decreases by 31 %

Step-by-step solution

Force between two point charges is given by F= k q₁ q₂ r² When r^ =r+20 % of r=1.2 r , then F^ = k q₁ q₂ (1.2 r)² = k q₁ q₂ 1.44 r² = F 1.44 Percentage decrease in force = F-F^ F 100= F- F 1.44 F 100= 0.44 1.44 100=31 %

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