Graph of induced EMF

[nightweaver066]

Question:
A student measured the magnetic flux through a solenoid of 100 turns and entered data into a spreadsheet. Her data is graphed below:

A good description of the potential difference generated in the solenoid would be:

What i thought it was: A

What the answer is: D

I thought it was A because there's the greatest change in flux (greatest gradient) and so greatest EMF would be induced at that point, which would be negative at first to oppose the change in flux.

Can anyone explain to me why i'm wrong and why the answer is D?

Thanks

 

[FraZzZz]

I'm pretty sure it's a sin wave, so it originates from y = 0.

Also, at the max cut in flux, there is an opposite according to Lenz' Law, so the induced EMF will be at a trough, whilst the cut in flux over time is at a peak.

 

[Mr Slick]

Lenz's Law !

 

[someth1ng]

emf=-change of flux/change of time

Highest rate of change of flux occurs when flux=0Wb

As the change is increasing (positive), the emf induced is negative.

The answer is A.

 

[nightweaver066]

emf=-change of flux/change of time

Highest rate of change of flux occurs when flux=0Wb

As the change is increasing (positive), the emf induced is negative.

The answer is A.

Exactly what i thought!

So i guess the answer for it is just wrong?

Thanks

 

[diasam]

Yep A. just think of it as a derivative, but take in account that pot diff is opposite to the derivative (Lenz's law), as it is induced EMF, not supplied.

 

[someth1ng]

Exactly what i thought!

So i guess the answer for it is just wrong?

Thanks

Yeah, you're right but I suppose B could be argued.

 

[nightweaver066]

Yeah, you're right but I suppose B could be argued.

lol yeah i see how it could as well, but majority would say A is right and others would argue B if they needed the mark.

 

[louigi04]

It's D because it is a solenoid not a motor