In a dark night, how does a torch enables us to see objects?
Light emitting from the torch falls on our eyes after being reflected by the object.
We see objects because light rays coming from the object falls on our eyes. Some objects are themselves a source of light e.g luminous bodies like stars, glowing bulb etc and to see them we do not require any other source of light. But other objects that are non-luminous are visible only when light from an external body fall on them and gets reflected to our eyes. The torch is the source of light which projects light on the object and the rays reflected from the object fall on our eyes, enabling us to see the object.