What methods can be used to obtain the EMF of induction in a conducting closed loop?

Hence it follows that the EMF of induction in the circuit can be obtained in three ways. One of them consists in the change over time of the magnetic induction of the field. This does not change the area of ​​the contour. Approximately, we can assume that the angle a between the direction of the normal to the contour and the direction of the magnetic induction vector at the points of the field bounded by the contour does not change either. The second way to obtain an EMF induction is associated with a change in the area of ​​the circuit in a uniform magnetic field. The third method consists in changing the orientation of the contour (angle a) relative to the induction vector of a uniform magnetic field. For example, when a frame with a current rotates in a uniform magnetic field, an EMF of induction appears in it.