Question

A wire of lenght $5cm$ is placed inside the solenoid near its center such that it makes an angle of $30$ with the axis of solenoid, The wire carries a current of 5A and the magnetic field due to solenoid is $2.5\times {10}^{-2}$ T. Magnetic force on wire is

• A. $3.12\times {10}^{-4}N$
• B. $31.2\times {10}^{-4}N$
• C. $312\times {10}^{-4}N$
• D. $0.312\times {10}^{-4}N$

Answer 1

The correct option is B $31.2\times {10}^{-4}N$

Given: i=5A, L=5 cm, B= 2.5$\times {10}^{-2}T,\theta ={30}^0$

Solution:As we know that the formula of magnetic force on a current carrying solenoid:

$F=Bilsin\theta =5\times 5\times {10}^{-2}\times 2.5\times {10}^{-2}\times \frac{1}{2}$

Magnetic force on wire is 31.25$\times {10}^{-4}$

Hence the correct answer is B.