Question

A solenoid of $1200$ tums is wound uniformly in a single layer on a glass tube $2\, m$ long and $02\, m$ in diameter The magnetic intensity at the center of the solenoid when a current of $2 A$ flows through it is:

• A. $2.4 \times 10^3 A m ^{-1}$
• B. $1.2 \times 10^3 A m ^{-1}$
• C. $1 Am ^{-1}$
• D. $2.4 \times 10^{-3} A m ^{-1}$

Answer 1

The Correct Option is B

1. The magnetic intensity \(H\) inside a solenoid is given by: \[ H = nI, \] where \(n\) is the number of turns per unit length and \(I\) is the current. 
2. Calculate \(n\): \[ n = \frac{\text{Total number of turns}}{\text{Length of solenoid}} = \frac{1200}{2} = 600 \, \text{turns/m}. \] 
3. Substituting \(n = 600 \, \text{turns/m}\) and \(I = 2 \, \text{A}\): \[ H = nI = 600 \times 2 = 1200 \, \text{A m}^{-1}. \] 
Thus, the magnetic intensity is \(\mathbf{1.2 \times 10^3 \, \text{A m}^{-1}}\). 
The magnetic intensity depends on the number of turns per unit length and the current flowing through the solenoid.