This is called Motional EMF.

• When a rod of length $l$ moves at speed $v$ inside a uniform magnetic field $B$, the Lorentz force ($F=qvB$) pushes charges to opposite ends of the rod.
• This separation of charge creates a potential difference.
• The induced EMF magnitude is: $E=Blv\sin \theta$ where $\theta$ is the angle between $\vec{v}$ and $\vec{B}$. For perpendicular motion, $\sin 90^{\circ }=1$.