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COMEDK20269 May 2026Evening ShiftPhysicsElectrostaticsActual

A pith ball of mass 'm' gram and charge 'Q' is suspended using a mass less silk thread near a large charged conducting metal sheet of area 'A' and surface charged density ' '. If the silk thread makes an angle with the metal sheet, then:

Options

  1. Amg
  2. BA
  3. C1

Correct answer

3

Step-by-step solution

The electric field near a large charged conducting metal sheet is given by E = ₀ . The electric force acting on the pith ball is F_e = QE = Q ₀ . The gravitational force acting downwards on the pith ball is W = mg . Let T be the tension in the silk thread. In equilibrium, the vertical and horizontal components of the tension balance the weight and the electric force respectively. T = mg T = Q ₀ Dividing the second equation by the first equation, we get: = Q mg ₀ From this expression, it is evident that . Answer:

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