Answer:
The Magnetic field is 59.13 mT.
Explanation:
Given that,
Number of turns = 400
Radius = 1.0 cm
Frequency = 90 Hz
Emf = 4.2 V
We need to calculate the angular velocity
Using formula of angular velocity
[tex]\omega=2\pi f[/tex]
[tex]\omega=2\times3.14\times90[/tex]
[tex]\omega=565.2\ rad/s[/tex]
We need to calculate the magnetic flux
Relation between magnetic flux and induced emf
[tex]\epsilon=NA\omega B[/tex]
[tex]B=\dfrac{\epsilon}{NA\omega}[/tex]
Put the value into the formula
[tex]B=\dfrac{4.2}{400\times\pi\times(1.0\times10^{-2})^2\times 565.2}[/tex]
[tex]B=0.05913\ T[/tex]
[tex]B=59.13\ mT[/tex]
Hence, The Magnetic field is 59.13 mT.