Magnetic Field of Rotating Coil

[dukesolice]

Magnetic field values are often determined by using a device known as a search coil. This technique depends on the measurement of the total charge passing through a coil in a time interval during which the magnetic flux linking the windings changes either because of the motion of the coil or because of a change in the value of B. As a specific example, calculate B when a 61-turn coil of resistance 194Ω and cross-sectional area 44.5m2 produces the following results: A total charge of 4.76E-4C passes through the coil when it is rotated in a uniform field from a position where the plane of the coil is perpendicular to the field to a position where the coil's plane is parallel to the field.

I know the formula emf = -change in flux, but I don't know how to get the change in the area and how to use the charge given.

 

[BvU]

Hello duke,

This looks a lot like homework, so please post there and use the template ! Show what you've done so far and we'll help you.

In exchange: when the coil is parallel to the field, flux is zero.
And charge is the integral of current over time - the time needed to turn the coil !

A drawing helps immensely, too !