Answer
We can rank the six plots according to the induced emf:
$1 = 3 \gt 2 = 5 \gt 4 = 6$
Work Step by Step
Note that the area $A$ of the loop is constant.
$\Phi = B~A$
$\frac{d\Phi}{dt} = \frac{dB}{dt}~A$
Note that $\frac{dB}{dt}$ is the slope of the $B$ versus $t$ graph.
plot 1 and plot 3: $\frac{dB}{dt} \gt 0$ and the slopes are equal for these two plots
plot 2 and plot 5: $\frac{dB}{dt} = 0$
plot 4 and plot 6: $\frac{dB}{dt} \lt 0$ and the slopes are equal for these two plots
We can write an expression for $\mathscr{E}$:
$\mathscr{E} = -\frac{d\Phi}{dt} = -\frac{dB}{dt}~A$
In plot 1 and plot 3, the flux increases in the +z direction. By Lenz's law, the induced current opposes this change. By the right hand rule, the induced current is in the clockwise direction. Therefore, the induced emf is also in the clockwise direction.
In plot 2 and plot 5, the flux does not change. There is no induced current and no induced emf.
In plot 4 and plot 6, the flux increases in the -z direction. By Lenz's law, the induced current opposes this change. By the right hand rule, the induced current is in the counterclockwise direction. Therefore, the induced emf is also in the counterclockwise direction.
We can rank the six plots according to the induced emf:
$1 = 3 \gt 2 = 5 \gt 4 = 6$
