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NEET2003PhysicsMagnetic Effects of CurrentActual

A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is:

Options

  1. AB 2
  2. BB
  3. C2 B
  4. D4 B

Correct answer

B. B

Step-by-step solution

Magnetic field induction at point insides the solenoid of length l , having n turns per unit length carrying current i . is given by B= ₀ n i If i is double and n is halved then B remains same.

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