Determining the direction of current due to a change in magnetic flux

[Eitan Levy]

Homework Statement

Let there be a magnetic field as posted below.

There is a square shaped loop with its center being at (2a, 2a,0). The length of the sides is 2a.

The loop is placed in the xy plane (z=0).

Determine the direction of the current in the loop.

Relevant Equations

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This is supposed to be very basic, where the loop is held there is a declining magnetic field in direction (-z), therefore the current is supposed to be clockwise. However in the answers it is said the the current is anti clockwise. That doesn't make sense to me.

Is there a mistake in the answers?

 

[TSny]

Your answer "clockwise" looks correct to me (assuming $B_0$ and $\beta$ are positive and assuming you're viewing from above the x-y plane.)

 

[hutchphd]

The induced current would oppose the change: so increase B in the -z direction. This is "clockwise" looking "down" at z (axial rotation vector in -z direction). Very clumsy nomenclature.

 

[etotheipi]

This is "clockwise" looking "down" at z (axial rotation vector in -z direction). Very clumsy nomenclature.

Besides the point, but related anyway, it did irritate me when my chemistry textbooks would just say an (+) enantiomer rotates the plane of polarisation clockwise, whilst a (-) enantiomer rotates the plane of polarisation anticlockwise. I mean, where are you viewing the beam from?!

 

[hutchphd]

And of course for the pedagogy it really didn't matter so long as you understood the existence of chirality. But agreed.