Engineers are designing a solar furnace that uses a large concave spherical mirror to concentrate sunlight onto a water-filled absorber located along the mirror’s principal axis. Sunlight arriving at Earth can be treated as a set of parallel rays.
(1) Using a verbally described ray diagram, explain where along the principal axis the engineers should place the absorber to achieve maximum concentration of solar energy. State whether the resulting solar image is real or virtual and whether it is upright or inverted.
(2) Suppose the absorber is accidentally positioned halfway between the focal point and the mirror’s surface. Predict qualitatively how this misplacement affects both the intensity of energy received and the apparent size of the solar image on the absorber, and explain your reasoning.
(3) The engineers consider replacing the concave mirror with a convex mirror of the same radius of curvature in an attempt to make the absorber more accessible. Predict whether a convex mirror could ever form a real solar image on an absorber located in front of the mirror. Provide a detailed explanation based on ray behavior.