How Is Average Induced Voltage Calculated in a Rotated Coil?

[dumbperson]

Homework Statement

A coil with 10 windings(radius 0,07m) is inside a homogenous magnetic(B=0,050T) field, it makes an angle of 90 degrees with the field lines so the magnetic flux is at it's max. Over a period of 0,050 seconds it gets turned by 180 degrees, what is the average induced voltage?

Homework Equations

phi=B*A
Uinduced=-N* dphi/dt

The Attempt at a Solution

The area is 0.07²*pi= 0,015393804 m²
So the magnetic flux in the situation before the turning is 0,015393804*0,050=0,0007696902 Wb
(I don't normally write numbers like this)
After it turns, this is the part i am unsure about, is the magnetic flux now -0,0007696902?
because phi=B*cos(180)*A
so the difference in magnetic flux is -2*(0,0007696902)
Then Uinduced = -10 * (-2*(0,0007696902))/0.050 = 0,31 volts. Is this correct?

I am verry sorry for my english. Thank you!

 

[dumbperson]

Anyone? :-)

 

[Redbelly98]

Welcome to Physics Forums.

Yes, that looks good. I didn't check your arithmetic, but your procedure and reasoning are correct. The flux simply changes sign (+ to -) when the coil is flipped 180 degrees, so the change in flux is 2x the value of the flux.

 

[dumbperson]

Thank you very much !

 

[rwisz]

I would suggest double checking your calculations and units to ensure accuracy. The magnetic flux after the turning would not be negative, as the angle of 180 degrees represents a complete rotation, so the cosine would be 1. Additionally, make sure to use the correct units for magnetic flux (Webers or Wb) and time (seconds) in your calculations. Overall, your approach seems correct and the final answer of 0.31 volts seems reasonable. However, it is always good practice to double check your work and units to ensure accuracy.