wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Two coaxial long solenoids of equal lengths have current, i1, i2, number of turns per unit length n1,n2 and radius r1,r2 respectively. If n1i1=n2i2 and the two solenoids carry current in opposite sense, the magnetic energy stored per until length is [r2>r1]

A
μ02n21i21π(r22r21)
loader
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
μ0n21i21π(r22r21)
loader
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
μ02n21i21πr21
loader
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
μ02n22i22πr22
loader
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A μ02n21i21π(r22r21)

Solution:-

Magnetic field is non zero only in the region between the two solenoids where,

B=μ0n2i2
energy stored per unit volume =B22μ0=μ0n22i222
The energy per unit length=energy per unit volume x area of cross section where,
B0
=μ0n22i222π[r22r21]=μ0n21i212π[r22r21] , since nii1n2i2

Hence the correct option is A

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Torque on a Magnetic Dipole
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon
footer-image