A plane mirror is fixed 50 cm above the bottom of a tank. Water depth is 8 cm and refractive index is 4/3. A small bulb is at the bottom. Find the distance of the final mirror image from the bottom in cm.

Question

G1 Physics · Accepted Answer

Viewed from air, the bulb's apparent depth below the water surface is d/μ = 8/(4/3) = 6 cm. The mirror is 50-8 = 42 cm above the water surface, so the apparent object is 42+6 = 48 cm in front of the mirror. A plane mirror forms the image 48 cm behind it. Therefore the image is 50+48 = 98 cm above the tank bottom. Final value: 98