Convex and concave lenses can both be used to correct defects of vision. The most commonly occurring defects of vision are ‘short sightedness’ and ‘long sightedness’. People who are ...

Draw a ray from the object to the lens that is parallel to the principal axis. Once through the lens, the ray should pass through the principal focus. Draw a ray which passes from the object ...

(b) only concave. (c) only convex. (d) either plane or convex ... How far is the object placed from the lens? Draw the ray diagram. The point of intersection of these refracted rays gives the ...