From the above discussion it follows that the total time taken from a
point on the object to the corresponding point on the image is the same
measured along any ray For example, when a convex lens focusses light
to form a real image, although the ray going through the centre traverses
a shorter path, but because of the slower speed in glass, the time taken
is the same as for rays travelling near the edge of the lens Rationalised 2023-24
Physics
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10 4  COHERENT AND INCOHERENT
ADDITION OF WAVES
In this section we will discuss the
interference pattern produced by the
superposition of two waves