Consider a circular current carrying conducting coil.
If the radius of a current carrying coil is doubled keeping the current unchanged, what happens to the magnetic field directed along its axis at far off points?
Answer & explanation
Correct answer: option 3
Magnetic field due to a current carrying loop at a point far-off : B = \(\frac{\mu_{o}}{4\pi}\) \(\frac{2nIA}{x^{3}}\)
n : no. of turns in the coil
I : current through the coil
A : Area of the coil
As radius increases to double the value, the area of coil quadruples.