Question

Calculate the magnetic field due to a
circular coil of 500 turns and of diameter 0.1 m,
carrying a current of 7 A (a) at a point on the axis of
the coil distant 0.12 m (b) at the centre of the coil.
with explanation​

Answer 1

Explanation:

Number of turns, n = 200

Radius of the coil, r = 10 cm

Current in the coil, i = 2A

(a) Let the magnetic field at the centre of the coil is B.

As the relation for magnetic field at the centre of a circular coil is given by

(b) As magnetic field at any point P (say) on the axis of the circular coil is given by

Where x is the distance of the point from the centre of the coil.

As per the question

Magnetic field will drop to half of its value at the centre if the distance of that point from the centre of the coil along the axis of coil is equal to 7.66 cm.

Answer 2

Answer:

(a) 2.5 × 10^-3 Tesla

(b) 44 × 10^-2 Tesla

Explanation:

(a) n= 500, Current(I) = 7A, a = 0.1/2 = 0.05m, x = 0.812m,µ=10^-7

Magnetic field at a point on axis of the coil,

B = µ/4π . 2πnIa²/(a²+x²)³/²

Fill the values:-

B = 10^-7 × 2π×500×7×(0.05)²/{(0.05)²+(0.12)²}³/²

B= 2.5 × 10^-3 Tesla

(b) Magnetic field at centre of coil

B = µ/4π × 2πnI/a

B = 10^-7 ×2π×500×7/0.05

B = 44 ×10^-2 Tesla