According to the DMG, force effects extend from the Prime Material Plane into the Border Ethereal (DMG, page 48):
A traveler on the Ethereal Plane is invisible and utterly silent to someone on the overlapped plane, and solid objects on the overlapped plane don't hamper the movement of a creature in the Border Ethereal. The exceptions are certain magical effects (including anything made of magical force) and living beings.
Is the opposite also true? If I'm on the Ethereal Plane, can I cast Forcecage, Eldritch Blast, Magic Missile, etc. on a creature on the Prime Material Plane, and it will have the intended consequences?