An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$B through any circular area of radius a inside the solenoid, centred on and perpendicular to the solenoid axis is:
C)($\mu$0 $\pi$a2nI.)
D)2$\mu$0 $\pi$a2nI.
E)0.

Question

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$B through any circular area of radius a inside the solenoid, centred on and perpendicular to the solenoid axis is:
C)($\mu$0 $\pi$a2nI.) 
D)2$\mu$0 $\pi$a2nI. 
E)0.

Quizplus · Accepted Answer

The magnetic flux through any circular area inside the solenoid can be given by the formula:
Φ = B.A = B.(πa^2)
where B = μ0.n.I (from the expression for magnetic field inside a solenoid)
Substituting the value of B in the above equation, we get:
Φ = (μ0.n.I).(πa^2)
which is the same as option C. Therefore, the correct answer is C.

An Ideal Solenoid of Radius a Has N Turns Per ϕ\phiϕ

An Ideal Solenoid of Radius a Has N Turns Per $\phi$