In the equation shown in your image:

$B = \frac{N \mu_0 I R^2}{2 (z^2 + R^2)^{3/2}}$

Here’s what the variables represent:

• $z$: The distance along the axis from the center of the loop
• $I$: The current in the wire
• $N$: The number of loops in the coil
• $R$: The radius of the loop

This equation describes the magnetic field ($B$) on the axis of a circular current loop.

Would you like more details or have any specific questions? Here are five related questions to expand your understanding:

1. How does the magnetic field vary as you move along the axis of the loop ($z$)?
2. How does increasing the current $I$ affect the magnetic field?
3. What role does the number of turns $N$ play in the strength of the magnetic field?
4. How does the radius $R$ of the loop influence the field at a given point on the axis?
5. Can this formula be applied to solenoids, and if so, how would it differ?

Tip: In cases where $z = 0$, i.e., at the center of the loop, the magnetic field is strongest.