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JEE Main202330 Jan 2023Morning ShiftPhysicsMagnetic Effects of CurrentActual

A massless square loop, of wire of resistance 10 Ω , supporting a mass of 1 g , hangs vertically with one of its sides in a uniform magnetic field of 10 3 G , directed outwards in the shaded region. A dc voltage V is applied to the loop. For what value of V , the magnetic force will exactly balance the weight of the supporting mass of 1 g ? (If sides of the loop = 10 cm , g = 10 m s - 2 ) .

Options

  1. A1 10 V
  2. B100   V
  3. C1   V
  4. D10   V

Correct answer

D. 10   V

Step-by-step solution

For balancing of force, Magnetic force F m = weight of supporting mass m g . ∴ I L B = m g ∴ V R L B = m g           ∵ From Ohm's law ,   I = V R ∴ V = m g R L B = 1 × 10 - 3   kg 10   m   s - 2 10   Ω 0 . 1   m 10 3 × 10 - 4   T = 10   V

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