JEE Main 2026 — Ray Optics Question with Solution
JEE Main 2026 (24 January Shift 2)
Question
Distance between an object and three times magnified real image is 40 cm. The focal length of the mirror used is cm.
Choose an option
Show full solutionCorrect option: B
Correct answer
B-15
Step-by-step explanation
For a mirror with magnification m = -3 (real image), object and image distances satisfy |u| + |v| = 40 cm.
Since m = v/u = -3, we have v = -3u, giving u + 3u = 40, so u = 10 cm and v = -30 cm.
Using mirror formula:
Hence f = -15 cm.
Since m = v/u = -3, we have v = -3u, giving u + 3u = 40, so u = 10 cm and v = -30 cm.
Using mirror formula:
Hence f = -15 cm.
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