Calculating the RMS Value of Sinewave Voltage

[Vladi]

Homework Statement

I keep telling myself that this problem should be easy, but I keep getting the wrong answer. Any help is appreciated.
A generator has an armature with 500 turns, which cut a flux of 8.00 mWb during each rotation. Compute the back emf it develops when it runs as a motor at 1500 rpm.

Homework Equations

emf= 2pi*(N)(A)(B)(f)*cos(2pi)
Flux=B*A

The Attempt at a Solution

This is the best I could come up with.

 

[kuruman]

You have found the maximum value. Try finding the rms value.

 

[Vladi]

You have found the maximum value. Try finding the rms value.

If the rms speed is calculated with the following equation: Vrms=Vmax/sqrt(2), does that mean I must plug in the rms speed within the equation? I will give it a shot. Also, how do you know I should be calculating for the rms value? Thank your for your time. I meant to say rms frequency.

 

[NascentOxygen]

If the rms speed is calculated with the following equation: Vrms=Vmax/sqrt(2), does that mean I must plug in the rms speed within the equation? I will give it a shot. Also, how do you know I should be calculating for the rms value? Thank your for your time. I meant to say rms frequency.

No, there is no such thing as RMS speed. A sinewave voltage can be specified by its peak value, its peak-to-peak value, or its RMS value. Does one of these agree with the textbook answer?