Please answer this question clearly !: Problem 5: A thin hollow cylinder of radius a is surrounded co-axially by - Physics - Electromagnetic Induction

Question

Please answer this question clearly !:

Problem 5: A thin hollow cylinder of radius a is surrounded
co-axially by another hollow cylinder of radius b, where b > a
Both the cylinders form part of an electric circuit and a current I
flows through them as shown in the figure Find the
(a) self inductance per unit length
(b) magnitude of the pressure exerted on each cylinder and state
whether the force on each cylinder is tending to burst apart or to
collapse the cylinder

Vijay Shankar Yadav · Accepted Answer

Dear Student,
a) magnetic field due to inner cylinder will be  circular  around it so let a small strip of length l and width dr  between the inner and outer cylinder at distance r from centre of the inner cylinder  hence dφ=B
ldrwhere B=μ0I2πrso net flux through space between the inner and oueter cylinderφ=∫abμ0I2πrldr=μ0I2πlln(ba)φ=LIso inductance per unit length L=μ02πln(ba)b) magnetic field due to inner cylinder at distance b=μ0I2πbso force on  a strip of length l' and subtending  angle dθ on center of the inner cylinder=dF=I2πbbdθ l'μ0I2πbso total force =F=∫02πI2πdθ l'μ0I2πb=μ0I22πbl'area of curved surface =2πbl'Pressure=μ0I22πbl'2πbl'=μ0I24π2b2
Regard