Question

To construct a solenoid, you wrap insulated wire uniformly around a plastic tube 7.0 cm in diameter and 48 cm in length. You would like a 3.0 A current to produce a 2.6 kG magnetic field inside your solenoid. What is the total length of wire you will need to meet these specifications?

Answer 1

Given is:-

Length L = 0.48m

Diameter D = 0.07m

Current I = 3 A

Magnetic field  

Now,

Number of turns is given by

by plugging all the values we get

which gives us

Total length of the wire is

(Note: both expressions are same, we are using the above one)

by plugging all the values we get

which gives us

or