The speed of light in water is 2.25 × 10⁸ ms^-1. If the speed of light in vacuum is 3 × 10⁸ ms^-1, calculate the refractive index of water.

A concave mirror produces three times magnified real image of an object placed at 7 cm in front of it. Where is the image located?

Light enters from air into a glass plate having refractive index 1.5. What is the speed of light in glass? (Speed of light in vacuum is 3 × 10⁸ ms^-1)

Cross word puzzle

Across

2. Optical illusion due to refraction

4. A type of mirror that diverge the light rays

6. The nature of image formed when object is near the pole of concave mirror

7. Electromagnetic radiation visible to us

Down

1. The light ray sent back from a surface into the same medium

3. When magnification is negative, the nature of the image is ________

5. For concave mirror u and f are always __________

Light ray emerges from water into air. Draw a ray diagram indicating the change in its path in water.