Why does a water tank filled with water appear shallower when viewed from the top?
Due to refraction
Light rays from the bottom of the tank travel from water (optically denser) to air (rarer), and on crossing the interface they bend away from the normal. The eye traces these refracted rays back in straight lines, locating the bottom at a virtual image closer to the surface.
The relation is \(\mu = \dfrac{\text{real depth}}{\text{apparent depth}}\); since \(\mu_{water} \approx 1.33 > 1\), the apparent depth is less than the real depth. This effect is refraction — not reflection, diffraction, or total internal reflection.
| List-I (Relief Materials) | List-II (Color Code) |
| A. Shelter | I. Yellow |
| B. Clothes | II. Khaki |
| C. Food | III. Red |
| D. Medicine | IV. Brown |
Which of the following is NOT a state function or state variable in a thermodynamic system?