The focus of a plane mirror is defined as being at infinity because the reflected rays do not converge or intersect. Unlike concave mirrors, which have a real focal point where light rays converge, plane mirrors reflect light in such a way that the rays remain parallel after reflection. This leads to the conclusion that the focal point of a plane mirror cannot be virtual, as it does not create a point of convergence like a concave mirror does. The discussion emphasizes the paradoxical nature of defining infinity in optical terms.
PREREQUISITESStudents of physics, optical engineers, and anyone interested in understanding the fundamental principles of light reflection and mirror optics.
Sam Morse said:I read somewhere that the focus of a plane mirror is at infinity because rays after reflection from a plane mirror don't intersect anywhere. But why can't the focus be virtual as in case of concave mirror ?
The two parallell rays of light we use to determine the focal distance will still be parallell and with the same distance from each other at infinity.Sam Morse said:I read somewhere that the focus of a plane mirror is at infinity because rays after reflection from a plane mirror don't intersect anywhere. But why can't the focus be virtual as in case of concave mirror ?