To solve this problem we will apply the concepts related to magnetic flux and induced voltage. This last expression understood as the variation of the magnetic flux over time and, in turn, the magnetic flux expressed as the variation of the magnetic field in a certain area.
Magnetic flux through the circular coil is given as
[tex]\Phi_C = B(\pi r^2)[/tex]
The induced voltage is the change of the magnetic flux across the time, then
[tex]\epsilon_{emf,C} = \frac{B(\pi r^2)}{t}[/tex]
At the same time the magnetic flux through the square coil would be given as,
[tex]\Phi_S = B(r^2)[/tex]
And the induced voltage EMF will be
[tex]\epsilon_{emf,s} = \frac{B(r^2)}{t}[/tex]
Equating both expression we have
[tex]\epsilon_{emf,s} = \frac{\epsilon_{emf,C}tr^2}{\pi r^2t}[/tex]
[tex]\epsilon_{emf,s} = \frac{0.74V}{\pi}[/tex]
[tex]\epsilon_{emf,s} = 0.23355V[/tex]
Therefore the emf induced in the square coil is 0.23355V
