Define the principal focus of convex and concave mirrors. Define focal length. Which mirror has a positive focal length? Which has a negative focal length and why?
Principal focus: The point where parallel rays meet or appear to diverge after reflection. Focal length (f): The distance between the pole (P) and focus (F). Positive focal length: A convex mirror has a positive focal length because its focus is behind the mirror. Negative focal length: A concave mirror has a negative focal length … Read more