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Question
Explain the rules for obtaining images formed by a convex lens with the help of ray diagram.
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Solution
- Rule 1: When a ray of light strikes the convex or concave lens obliquely at its optical centre, it continues to follow its path without any deviation.
Rays passing through the optical centre - Rule-2: When rays parallel to the principal axis strikes a convex or concave lens, the refracted rays are converged to (convex lens) or appear to diverge from (concave lens) the principal focus
Rays passing parallel to the optic axis - Rule-3: When a ray passing through (convex lens) or directed towards (concave lens) the principal focus strikes a convex or concave lens, the refracted ray will be parallel to the principal axis
Rays passing through or directed towards the principal focus
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| Position of Object | Position of Image | Nature of Image |
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| Beyond 2F1 | (b) ______ | (c) ______ |
| At 2F1 | (d) ______ | Real, inverted, same size (as object) image |
| Between F1 and 2F1 | Beyond 2F2 | (e) ______ |
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