In an experiment to measure the focal length (f) of a convex lens, the magnitude of object distance (x) and the image distance (y) are measured with reference to the focal point of the lens. The y-x plot is shown in figure. The focal length of the lens is cm. [figure]
Ray Optics and Optical Instruments
Previous year questions with solutions · 2024 – 2026
Year-wise statistics questions · papers · average per paper · weightage
| Year | Questions | Papers | Avg / paper | Weightage |
|---|---|---|---|---|
| 2026 | 34 | 19 | 1.8 | 7.16% ▼ 20.9% vs last year |
| 2025 | 43 | 19 | 2.3 | 9.05% ▲ 185.9% vs last year |
| 2024 | 19 | 20 | 0.95 | 3.17% |
A convex mirror of radius of curvature 30 cm forms an image that is half the size of the object. The object distance is :
- -45 cm
- -15 cm
- 45 cm
- 15 cm
A biconvex lens of refractive index 1.5 has a focal length of 20 cm in air. Its focal length when immersed in a liquid of refractive index 1.6 will be:
- -16 cm
- +16 cm
- +160 cm
- -160 cm
If the distance between object and its two times magnified virtual image produced by a curved mirror is 15 cm, the focal length of the mirror must be:
- -10 cm
- -12 cm
- 15 cm
- 10/3 cm
If the refractive index of the material of a prism is ( A2 ), where A is the angle of prism then the angle of minimum deviation will be
- - 2A
- 2-2A
- - A
- 2-A
Two immiscible liquids of refractive indices 85 and 32 respectively are put in a beaker as shown in the figure. The height of each column is 6 cm. A coin is placed at the bottom of the beaker. For near normal vision, the apparent depth of the coin is 4 cm. The value of is . [figure]