A certain elastic conducting material is stretched into a circular loop of 1.6 cm radius. It is placed with its plane perpendicular to a uniform 0.8 T magnetic field. When released, the radius of the loop starts to shrink at an instantaneous rate of 75.0cm/s. What emf is induced in the loop at that instant in units of V?

Respuesta :

Answer:

Induced emf in the loop is 0.0603 volts.

Explanation:

It is given that,

Radius of the circular loop, r = 1.6 cm = 0.016 m

Magnetic field, B = 0.8 T

When released, the radius of the loop starts to shrink at an instantaneous rate of 75.0 cm/s, [tex]\dfrac{dr}{dt}=75\ cm/s=0.75\ m/s[/tex]

We need to find the magnitude of induced emf at that instant. Induced emf is given by :

[tex]\epsilon=\dfrac{-d\phi}{dt}[/tex]

Where

[tex]\phi[/tex] is the magnetic flux, [tex]\phi=B\times A[/tex]

[tex]\epsilon=\dfrac{-d(BA)}{dt}[/tex], A is the area of cross section

[tex]\epsilon=-\dfrac{-d(B(\pi r^2))}{dt}[/tex]

[tex]\epsilon=-2\pi r B(\dfrac{dr}{dt})[/tex]

[tex]\epsilon=-2\pi \times 0.016\times 0.8 \times 0.75\ m/s[/tex]

[tex]\epsilon=0.0603\ V[/tex]

So, the induced emf in the loop is 0.0603 volts. Hence, this is the required solution.