- #1

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- Homework Statement
- A magnetic field runs through a coil of area ##A##, parallel to its normal direction, and with intensity increasing at a constant rate ##\frac{dB}{dt}=0.20Ts^{-1}##.

##\rightarrow## suppose even the area can be changed at a constant rate; what should this rate be, in the instant when ##B=1.8T##, so that the induced E.M.F. in the coil is ##0##?

DISCLAIMER: I haven't studied integrals yet

- Relevant Equations
- Faraday-Neumann-Lenz

I managed to solve this problem by writing the total E.M.F. as the sum of the one which would have been induced with only the magnetic field varying(and constant ##A##), and that with only the area varying(and constant ##B##).

However, I got to this solution(which doesn't totally convince me) in a bit cumbersome way... and I cannot really get why it is correct to sum the individual E.M.F.s, while it isn't to find the ##EMF(t)=2\frac{\Delta B}{\Delta t} \cdot \frac{\Delta A}{\Delta t} \cdot t## simply by deriving the flux at given instant t.

The answer must be silly, but I'm drowning in a cup of water :)

However, I got to this solution(which doesn't totally convince me) in a bit cumbersome way... and I cannot really get why it is correct to sum the individual E.M.F.s, while it isn't to find the ##EMF(t)=2\frac{\Delta B}{\Delta t} \cdot \frac{\Delta A}{\Delta t} \cdot t## simply by deriving the flux at given instant t.

The answer must be silly, but I'm drowning in a cup of water :)