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QJEEM19Ph3857: JEE Main 2019 Physics - Class 12 JEEM19Ph3857 Solution: A thin convex lens L (refractive index = 1.5) is placed on a…
A thin convex lens L (refractive index = 1.5) is placed on a plane mirror M. When a pin is placed at A, such that OA = 18 cm, its real inverted image is formed at A itself, as shown in figure. When a liquid of refractive index μ1 is put between the lens and the mirror, The pin has to be moved to A', such that OA' = 27 cm, to get its inverted real image at A' itself. The value of μ1 will be :- 
Multiple Choice Options
- A
- B `3/2
- C 2
- D `4/3
Step-by-Step Verified Solution
For image to form at object itself, says must retrace their path back to object. Hence must incident on mirror normally.
Case 1: Object will be at focus of lens
Case 2: Retraction at 1st surface:
2nd retraction:
From (i) and (ii)
Case 1: Object will be at focus of lens
Case 2: Retraction at 1st surface:
2nd retraction:
From (i) and (ii)