Answer:
Given
Current in the long wire I = 497 A
r = 1.3 m
Length of the small wire , L = 0.01 m
Current in the small wire , i = 12 A
a) Magnetic field given as
[tex]B = \dfrac{\mu_oI}{2\pi r}[/tex]
[tex]B=\dfrac{4\pi \times 10^{-7}\times 497}{2 \times \pi \times 1.3}[/tex]
B=0.000076 T
B=7.6 x 10⁻⁵ T
b)
We know that force F given as
F= I B L
The force on the small wire is
F= i . B L
F= 12 x 0.000076 x 0.01
F=912 x 10⁻⁸ N