Question 6:
Which of the following lenses would you prefer to use while reading small letters
found in a dictionary?
(a) A convex lens of focal length 50 cm
(b) A concave lens of focal length 50 cm
(c) A convex lens of focal length 5 cm
(d) A concave lens of focal length 5 cm
Answer:
(c) A convex lens gives a magnified image of an object when it is placed between
the radius of curvature and focal length. Also, magnification is more for convex
lenses having shorter focal length. Therefore, for reading small letters, a convex
lens of focal length 5 cm should be used.
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