The circuit shown is in a uniform magnetic field that is into the page. The total current in the circuit is 0.20 A, flowing counterclockwise. At what rate is the magnitude of the magnetic field changing? Is it increasing or decreasing?
Square wire loop with base and height of 12 cm
One 4 V battery and one 10 Ω resistor
Homework Equations(first ever post so sorry for the poor formatting)[/B]
dB = (μ0 * (I*ds)x(r))/(4πr2)
Bloop = (μ0*I)/(2r)
The Attempt at a Solution
Given the direction of the current and using the right hand rule, the magnetic field produced by the current opposes the uniform one into the page, so it's magnitude is decreasing. However, the given equations don't fit with a square loop. I initially tried the second equation, but since r is changing it didn't work. I'm assuming the first equation is the one that's needed since we're looking for the change in magnetic field but I can't seem to find what ds should be.
Thanks for the help!