Question

An L-shaped metal wire carries a current of 4.50A, the length of each straight section is 2m, lies in a uniform magnetic field B=8iT. find the magnetic force on the wire ?A)0B)72kNC)36kND)72jNE)36jN

Answer 1

We are given the following information.

Current = 4.50 A

Length of wire = 2 m

Magnetic field = 8i T

We are asked to find the magnetic force on the wire.

Recall that the magnetic force is given by

`F=i\cdot\vec{L}*\vec{B}\sin\theta`

Where θ is the angle between the magnetic field and the wire.

Notice that the magnetic field and wire in the horizontal (x) direction are parallel meaning that the angle between them is 0° hence, there will be no magnetic force acting in the x-direction.

On the other hand, the magnetic field and wire in the vertical (y) direction are perpendicular meaning that the angle between them is 90° hence maximum magnetic force will be acting in the y-direction.

`\begin{gathered} F=4.5\cdot(2j*8i)\sin(90\degree) \\ F=4.5\cdot(2j*8i)(1) \\ F=4.5\cdot(16k) \\ F=72k\;N \end{gathered}`

Therefore, the magnetic force acting on the wire is 72k N.

Option B is the correct answer.