Answer:
When the magnetic field is tilted so it is no longer perpendicular to the page.
When the magnetic field gets stronger.
When the size of the loop decreases.
Explanation:
According to the Faraday-Lenz law, the change of the magnetic flux over time causes an induced current, this flux is given by:
Therefore, there will be a variable magnetic flux, when the magnitude of the magnetic field (B) changes over time, when the area of the loop (S) changes over time and / or when the angle () between the field and the surface vector changes over time.