Answer:
B.975 Turns
Explanation:
Given that
l = 150 cm
r= 4 cm
L = 0.004 H
A=πr²
We know that self inductance given as
[tex]L=\dfrac{\mu_o N^2A}{l}[/tex]
[tex]N=\sqrt{\dfrac{lL}{\mu_o A}}[/tex]
Now by putting the values
[tex]N=\sqrt{\dfrac{0.004\times 1.5}{4\times \pi \times 10^{-7}\times \pi \times 0.04^2}}[/tex]
N=974.62
Therefore the number of turns N= 975
The answer is B.