Question

A very long solenoid has 8400 windings and a length 7 m . If the field inside is 2 π ×10^-3T . The current in the windings is about

Answer 1

Answer:

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Answer 2

Given: A very long solenoid has 8400 windings and a length 7 m and the field inside is 2π×10⁻³ T.

To find: The current in the windings.

Solution:

• The magnetic field of a long solenoid is given by the formula,

        $B = \frac{\mu _{o} N I}{l}$

• Here, B is the field, μ₀ is the permeability of free space, N is the number of windings, I is the current in the windings and l is the length of the solenoid.
• On replacing the terms with the values given in the question, the obtained equation is,

        $2\pi * 10^{-3} T = \frac{4\pi * 10^{-7}NA^{-1} * 8400 * I}{7m}$

• On rearranging and solving further, the value of I is found to be,

        $I = 4.17 A$

Therefore, the current in the windings is 4.17 A.