Question

A magnetic field of `100G(1G=10^-4T)` is required which is uniform in a region of linear dimension about `10cm` and area of cross section about `10^-3m^2`. The maximum current carrying capacity of a given coil of wire is `15A` and the number of turns per unit length that can be wound round a core is at most `1000turns m^-1`. Suggest some appropriate design particulars of a solenoid for the required purpose. Assume the core is not ferromagnetic.

Answer 1

Here, `B=100G=10^-2T`, `I=15A`, `n=1000m^-1`
As, `B=mu_0nI` or `nI=(B)/(mu_0)=(10^-2)/(4pixx10^-7)=(10^-2)/(4xx(22//7)xx10^-7)=7955~~8000`
We may have, `I=10A`, `n=800`. The core length may be `50cm` having 400 turns and area of cross-section is `5xx10^-3m^2` which is five times given value.