What is the magnetic field at the center of the loop in the figure? (Figure 1)
Answer
The field will be sum of the fields due to a current carrying wire and a circular loop,
B=\frac{\mu_{0} I}{2 \pi a}+\frac{\mu_{0} I}{2 a}=\frac{4 \pi \times 10^{-7} \times 5}{2 \times 0.01}\left(\frac{1}{\pi}+1\right)=4.14 \times 10^{-4} T