Answer:
![B=2.91\ \mu T](https://img.qammunity.org/2022/formulas/physics/college/xas96j5hr426shp5xhc981otyfpy13bkyq.png)
Step-by-step explanation:
Given that,
The current in the loop, I = 2 A
The radius of the loop, r = 0.4 m
We need to find the magnetic field at a distance 0.09 m along the axis and above the center of the loop. The formula for the magnetic field at some distance is given as follows :
![B=(\mu_o)/(4\pi )(2\pi r^2 I)/((r^2+d^2)^(3/2))](https://img.qammunity.org/2022/formulas/physics/college/k8uo15j1lhuo0q4n6ijfn7woa394w3g6hb.png)
Put all the values,
![B=10^(-7)* (2\pi * 0.4^2 * 2)/((0.4^2+0.09^2)^(3/2))\\\\=2.91* 10^(-6)\ T\\\\or\\\\B=2.91\ \mu T](https://img.qammunity.org/2022/formulas/physics/college/9z1dpql9cgfemprg2xa4e5jh6eui8it3a3.png)
So, the required magnetic field is equal to
.