COMEDK2022PhysicsRay Optics
A plane glass mirror of thickness 3 cm of material of = 3 2 is silvered on the back surface. When a point object is placed 9 cm from the front surface of the mirror, then the position of the brightest image from the front surface is
Options
- A9 ~cm
- B11 ~cm
- C12 ~cm
- D13 ~cm
Correct answer
D. 13 ~cm
Step-by-step solution
The brightest image is formed by light that refracts into the glass, reflects from the silvered back surface, and refracts back out. Refraction at front surface: Apparent distance of object from front surface as seen inside glass: u' = u = 3 2 9 = 13.5 cm Reflection at silvered back surface: Distance of apparent object from back mirror = 13.5 + 3 = 16.5 cm Plane mirror forms image 16.5 cm behind the back surface. Distance of this image from the front surface (inside glass) = 16.5 + 3 = 19.5 cm Refraction back out a