Answer:
[tex]\phi = 7.4 \times 10^{-6} Wb[/tex]
Explanation:
Magnetic field due to a long solenoid at the center is given by
[tex]B = \frac{\mu_o N i}{L}[/tex]
here we know that
N = 300
L = 30 cm
i = 12 A
now magnetic field is given as
[tex]B = \frac{(4\pi \times 10^{-7})(300)(12)}{0.30}[/tex]
[tex]B = 0.015 T[/tex]
Now magnetic flux through the disc is given as
[tex]\phi = B.A[/tex]
[tex]\phi = (0.015)(\pi r^2)[/tex]
[tex]\phi = (0.015)(\pi)(0.0125)^2[/tex]
[tex]\phi = 7.4 \times 10^{-6} Wb[/tex]
