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Question
When sunlight is concentrated on a piece of paper by a spherical mirror or lens, then a hole can be burnt in it. For doing this, the paper must be placed at he focus of:
(a) either a convex mirror or convex lens
(b) either a concave mirror or concave lens
(c) either a concave mirror or convex lens
(d) either a convex mirror or concave lens
Solution
either a concave mirror or a convex lens
Both a concave mirror and a convex lens focus parallel light beams coming from a distant object onto the focus.
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