Question

a current I flows through a long straight conductor which is bent into a circular loop of radius R in the middle as shown in the figure

What will be the magnetic feild at point O?​

Answer 1

Answer:

As the current is clockwise the magnetic fields will be towards the SOUTH !

Answer 2

Given:

Current I flows through a long straight conductor which is bent into a circular loop of radius R.

To Find:

The magnetic feild at point O

Solution:

Magnetic field at O due to the straight part of the wire, is given by,

• Bstraight = $\frac{\mu_0}{2\pi R}$ I
• Its direction will be upwards, by Right hand Thumb rule.

Magnetic field at O due to the loop of radius R,

• Bloop = $\frac{\mu_0}{4\pi R^{2}}$ x I x 2πR = $\frac{\mu_0}{2R}$ I
• Its direction will be downwards.

Therefore net magnetic field at O is given by,

• B = Bloop + Bstraight
• B = $\frac{\mu_0}{2R}$ I - $\frac{\mu_0}{2\pi R}$ I , downwards.
• B = $\frac{\mu_0}{2\pi R}$ I ( π - 1 ) downwards.

The magnetic feild at point O will be B = $\frac{\mu_0}{2\pi R}$ I ( π - 1 ) downwards.