# A Closely Wound Solenoid 80 Cm Long Has 5 Layers of Windings of 400 Turns Each. the Diameter of the Solenoid is 1.8 Cm. If the Current Carried is 8.0 A, Estimate the Magnitude Of B Inside the Solenoid Near Its Centre. - Physics

A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm. If the current carried is 8.0 A, estimate the magnitude of inside the solenoid near its centre.

#### Solution

Length of the solenoid, l = 80 cm = 0.8 m

There are five layers of windings of 400 turns each on the solenoid.

∴ Total number of turns on the solenoid, N = 5 × 400 = 2000

Diameter of the solenoid, D = 1.8 cm = 0.018 m

Current carried by the solenoid, I = 8.0 A

Magnitude of the magnetic field inside the solenoid near its centre is given by the relation,

B=(mu_0NI)/l

Where,

mu_0 = Permeability of free space = 4π × 10–7 T m A–1

B=(4pixx10^-7xx2000xx8)/(0.8)

=8pixx10^-3=2.512xx10^-2T

Hence, the magnitude of the magnetic field inside the solenoid near its centre is 2.512 × 10–2 T.

Concept: Magnetic Field on the Axis of a Circular Current Loop
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#### APPEARS IN

NCERT Class 12 Physics Textbook
Chapter 4 Moving Charges and Magnetism
Q 8 | Page 169