InterviewSolution
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InterviewSolution
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A ray of light falls on a plane mirror. When the mirror is turned, about an axis at right angles to the plane of mirror by `20^(@)` the angle between the incident ray and new reflected ray is `45^(@)`. The angle between the incident ray and original reflected ray was therefore.A. `35^ (@)` or `50^ (@)`B. `25^(@)` or `65^(@)`C. `45^(@)` or `5^(@)`D. None of these |
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Answer» Correct Answer - D Let i is the angle between incident ray and original reflected ray, Then initial angle between them will be `180^(@)-2i`. When mirror is rotated by `20^(@)` , then reflected ray will rotate by `40^(@)` `:. 180^(@) -2i+- 40^(@) =45^(@)` Solving we get, ` i=47.5^(@) or 87.5^(@)`. |
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