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Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30^ with each other. When suspended in a liquid of density 0.8 ~g ~cm ⁻³ , the angle remains the same. If density of the material of the sphere is 16 ~g ~cm ⁻³ , the dielectric constant of the liquid is

Options

  1. A4
  2. B3
  3. C2
  4. D1

Correct answer

C. 2

Step-by-step solution

From F.B.D of sphere, using Lami's theorem F mg = when suspended in liquid, as remains same, F ^ mg (1- d ) = using (i) and (ii) F m g = F^ m g (1- d ) where, F^ = F K F mg = F ^ mg K (1- d ) or K = 1 1- d =2

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