# Find the magnetic field at point P in the figure below, where I = 15 A and R = 20 cm.

$\begin{array}{1 1} 24 \mu T \\ 24 mT \\ 2.4\;\mu T \\ 2.4 mT\end{array}$

The magnetic field at the center of a current loop with current $I$ and radius $R$ is $B = \large\frac{\mu_o I}{2R}$
What we have here is a half-loop, therefore
$B = \large\frac{1}{2} $$\times \large\frac{\mu_o I}{2R} \Rightarrow B = \large\frac{1}{2}$$\times \large\frac{4\pi \times 10^{-7}N/A^2 \times 15A}{2 \times 20cm}$
$\Rightarrow B \approx 24 \mu T$