#### chukie

A circular coil, with radius of 10 cm, and 25 turns, rotates in a constant magnetic field of
strength 2.4 T, with the axis of rotation perpendicular to the direction of the magnetic
field.
If the coil rotates at a frequency of 50 Hz, what is the induced peak voltage?

Okay so I know the equation to use is:
emf=-Ndelta flux/delta t

I know all the variables in the equation except for time. I was wondering how you calculate the time. Is it just 1/50Hz?

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#### dynamicsolo

Homework Helper
What is happening during that 1/50 of a second? The coil is being spun around an axis perpendicular to the external magnetic field. So what is going on with the flux through the coil? (The magnetic field strength is not changing at all!)

#### chukie

What is happening during that 1/50 of a second? The coil is being spun around an axis perpendicular to the external magnetic field. So what is going on with the flux through the coil? (The magnetic field strength is not changing at all!)
So is the change in time just 1/50=0.02s? The number seems a bit small to me.

#### Redbelly98

Staff Emeritus
Homework Helper
Have you had calculus and used derivatives yet?

You would start by figuring out an expression for the flux as a function of time, then take the derivative.

#### Redbelly98

Staff Emeritus
Homework Helper
So is the change in time just 1/50=0.02s? The number seems a bit small to me.
No. After 0.02s (or 1 period), the flux will be exactly what it was at 0.00s. This is because the flux is a periodic function of time, with period 0.02s.

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