- #1
dukesolice
- 4
- 0
Homework Statement
[/B]
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 44.5m^2 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.
Homework Equations
emf = -change in flux
The Attempt at a Solution
emf = -d/dt (integral of B dot dA)
The change in flux is from when the coil is perpendicular to the field to when the coil is parallel to the field. So 90 degrees. But I don't know how to get the change the in area, and how to use the charge and resistance.