Explanation:
It is given that,
Radius of loop, r = 78 mm = 0.078 m
Current, I = 114 A
(a) Magnetic field strength of the circular loop is given by :
[tex]B=\dfrac{\mu_oI}{2R}[/tex]
[tex]B=\dfrac{4\pi \times 10^{-7}\times 114}{2\times 0.078}[/tex]
B = 0.000918 T
or
[tex]B=9.18\times 10^{-4}\ T[/tex]
(b) Energy density at the center of the loop is given by :
[tex]U=\dfrac{B^2}{2\mu_o}[/tex]
[tex]U=\dfrac{(0.000918)^2}{2\times 4\pi \times 10^{-7}}[/tex]
[tex]U=0.335\ J/m^3[/tex]
Hence, this is the required solution.