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A closely wound rectangular coil of 80 turns has dimensions of 25.0 cm by 40.0 cm. The plane of the coil is rotated from a position where it makes an angle of 37.0 ∘ with a magnetic field of 1.30 T to a position perpendicular to the field. The rotation takes 0.0900 s . What is the average emf EMF induced in the coil?What is the magnitude of the average emf E induced as the coil is rotated?E= ________ V

Respuesta :

Answer:

[tex]E=0.2909\ V[/tex]

Explanation:

Given:

no. of turns in the coil, [tex]n=80[/tex]

magnetic field, B = 1.3 T

area of the coil, [tex]A=(0.25\times 0.4)=0.1\ m^2[/tex]

initial angle of the coil plane from the magnetic field, [tex]\psi_i=37^{\circ}[/tex]

final angle of the coil plane from the magnetic field, [tex]\psi_f=90^{\circ}[/tex]

time taken to rotate through the angle, [tex]dt=0.09\ s[/tex]

Now  we find initial and final flux through the coil:

[tex]\phi_i=B.A\ cos\ \psi[/tex]

[tex]\phi_i=1.3\times 0.1\ cos\ 37^{\circ}[/tex]

[tex]\phi_i=0.1038\ Wb[/tex]

&

[tex]\phi_f=B.A\ cos\ \psi[/tex]

[tex]\phi_f=1.3\times 0.1\ cos\ 90^{\circ}[/tex]

[tex]\phi_f=0.13\ Wb[/tex]

[tex]\therefore d \phi=\phi_f-\phi_i[/tex]

[tex] d \phi=0.13-0.1038[/tex]

[tex] d \phi=0.0262\ Wb[/tex]

Now we know according to Faraday's Law, emf induced in a coil is given by:

[tex]E=n.\frac{d \phi}{dt}[/tex]

[tex]E=80\times \frac{0.0262}{0.09}[/tex]

[tex]E=0.2909\ V[/tex]