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Two balls with equal charges are in a vessel with ice at - 10 ° C at a distance of 25 c m from each other. On forming water at 0 ° C , the balls are brought nearer to 5 c m for the interaction between them to be same. If the dielectric constant of water at 0 ° C is 80 , the dielectric constant of ice at - 10 ° C is

Options

  1. A40
  2. B3.2
  3. C20
  4. D6.4

Correct answer

B. 3.2

Step-by-step solution

( - 10 ° C ice) ( 0 ° C water) q 1               k 1              r 1 = 25 c m q 2     q 1           k 2 = 80           r 2 = 5 cm q 2 Given F i c e = F w a t e r 1 4 πε 0    q 1 q 2 k 1 r 1 2 = 1 4 πε

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