Answer:
3.4 x 10^-4 T
Explanation:
A = 1.5 x 10^-3 m^2
N = 50
R = 180 ohm
q = 9.3 x 106-5 c
Let B be the magnetic field.
Initially the normal of coil is parallel to the magnetic field so the magnetic flux is maximum and then it is rotated by 90 degree, it means the normal of the coil makes an angle 90 degree with the magnetic field so the flux is zero .
Let e be the induced emf and i be the induced current
e = rate of change of magnetic flux
e = dФ / dt
i / R = B x A / t
i x t / ( A x R) = B
B = q / ( A x R)
B = (9.3 x 10^-5) / (1.5 x 10^-3 x 180) = 3.4 x 10^-4 T