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MHT CET 2023 (14 May, Shift 1) · Other: Induction & Displacement Current

Other: Induction & Displacement Current question from MHT CET 2023 (14 May, Shift 1)

Q9MHT CET 2023 · 14 MAY · SHIFT 1Medium

Other: Induction & Displacement Current

A horizontal wire of mass 'mm', length 'll' and resistance 'RR' is sliding on the vertical rails on which uniform magnetic field 'BB' is directed perpendicular. The terminal speed of the wire as it falls under the force of gravity is ( g=g = acceleration due to gravity)

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Answer: (d)

  1. Falling wire: emf =Blv= Blv, current I=BlvRI = \frac{Blv}{R}, upward magnetic force F=BIl=B2l2vRF = BIl = \frac{B^2 l^2 v}{R}.
  2. At terminal speed the force balances weight: B2l2vtR=mg\frac{B^2 l^2 v_t}{R} = mg
  3. vt=mgRB2l2v_t = \frac{mgR}{B^2 l^2}
  4. So the answer is (d).
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