Question

In a physics laboratory experiment, a coil with 170 turns enclosing an area of 10.1 cm2 is rotated in a time interval of 4.70×10−2 s from a position where its plane is perpendicular to the earth's magnetic field to one where its plane is parallel to the field. The earth's magnetic field at the lab location is 6.7×10−5 T. What is the magnetic flux through each turn of the coil before it is rotated?

Answer 1

The definition of the magnetic flux allows us to observe how the magnetic field describes as a function of the area. Mathematically it can be expressed as

`\phi = BASin\theta`

Where

B = Magnetic Field

A = Area

`\theta =` Angle between the normal of the area and the magnetic field

Since the problem makes us intuit that we are talking about perpendicular surfaces we have that the angle is 90 °

Our values are given by

`B = 4*10^(-5)T`

`A = 10.1*10^(-4)m^2`

Replacing in our equation we have to

`\phi = BASin\theta`

`\phi = (4*10^(-5))(10.1*10^(-4))Sin(90)`

`\phi = 4.04*10^(-8)Wb`

Therefore the magnetic flux thorugh each turn of the coil before it is rotated is
`4.04*10^(-8)Wb`

NOTE: We do not use the 170 turns because the question asked us about the magnetic flux in EACH one of them.