An emf is induced by rotating a 1247 turn, 20.0 cm diameter coil in the Earth's 6.13 10-5 T magnetic field. What average emf is induced, given the plane of the coil is originally perpendicular to the Earth's field and is rotated to be parallel to the field in 10.0 ms

The average induced emf = 2.4015V

Explanation:

Given.

Turn, N = 1247

diameter coil = 20cm

Magnetic field = 6.13 * 10^-5T

Parallel to field = 10ms

From Faraday law, we know that the emf induced in a coil is directly proportional to the rate of change of magnetic flux through the coil.

This is given by;

-Nd∅b/ft

= -N * d/dt(BA)

= -NB*dA/dt

= - 1247 * 6.13 * 10^-5 * (0 - (π * 0.10²))/0.001

= 2.40146798192322743920646

= 2.4015V Approximated

The average induced emf = 2.4015V

wavelegth as in spectrum red oygbiv

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.