A cylindrical bucket of depth 60 cm is partly filled with a liquid of refractive index 1.5 and with oil (on top of the liquid) of refractive index 2. It appears that the volumes of air, liquid and oil are equal to an observer viewing from the top. The apparent depth of the bucket is α cm. Fill (α/5) in the OMR sheet.
Options

Question

A cylindrical bucket of depth 60 cm is partly filled with a liquid of refractive index 1.5 and with oil (on top of the liquid) of refractive index 2. It appears that the volumes of air, liquid and oil are equal to an observer viewing from the top. The apparent depth of the bucket is α cm. Fill (α/5) in the OMR sheet.

Options

G1 Physics · Accepted Answer

Derived solution: Step 1: Use Snell’s law at each plane interface. For paraxial viewing through a plane surface, apparent depth = real depth × n(observer)/n(object medium). Step 2: Substitute the values given in the question and apply the geometry/sign convention shown. Step 3: On simplification the result is 8. Therefore the correct option is A.