Question

A wire of length 0.26 m is bent to form a circular loop if 2 A of current is flowing through the loop calculate magnetic field at a point P which is at a distance 0.15 m from its centre

Answer 1

We are given a circular current carrying conducting loop. Need to find the magnetic field B (flux density) at a distance d from the center of the loop along the axis of the loop.   Using Biot-Savart's law for magnetic field we can derive the formula.

Current through the loop = i

B = 54 * 10⁻⁶ T

d = 4 cm = 0.04 m

radius = a = 3 cm = 0.03 m

              B = μ i a² / [2 (d² + a²)³/² ]

              54 * 10⁻⁶  = 4 π * 10⁻⁷ * i * 0.03² / [2 * 0.05³]   T

=>        i  = 1.193 Amp

Magnetic field at the center of the loop is given by

   B = μ i / (2 a)

       = 4 π * 10⁻⁷ * 1.193 /(2 * 0.03) T

       = 2.50 * 10⁻⁵ T