Answer:
B'=2 μT
Explanation:
Given that
Distance ,d= 2 cm
magnetic field ,B= 4 μT
we know that magnetic filed at a distance d is given as
[tex]B=\dfrac{\mu I}{2\pi d} ----1[/tex]
I=Current
When the distance become 4 cm
d' = 4 cm
d'= 2 d
[tex]B'=\dfrac{\mu I}{2\pi d'}[/tex]
[tex]B'=\dfrac{\mu I}{2\pi \times 2d}\ --2[/tex]
From equation 1 and 2
[tex]\dfrac{B'}{B}=\dfrac{\dfrac{\mu I}{2\pi \times 2d}}{\dfrac{\mu I}{2\pi \times d}}[/tex]
[tex]B'=\dfrac{B}{2}[/tex]
[tex]B'=\dfrac{4\mu }{2}\ T[/tex]
B'=2 μT
