Question

1. A mixture of red, blue, and green light rays is passed through a convex lens, as illustrated in the diagram below. State whether the ray passes through a single point or through different points on the principal axis after refraction.
   
2. Name the invisible radiation which is studied using the quartz prism.
3. State one use of the radiation mentioned by you in (b) above.
4. Name one type of radiation with a wavelength greater than that of the radiation mentioned by you in (b) above.

Answer 1

1. Different points on the principal axis (red is least deviation, blue is most).
2. Ultraviolet radiation
3. Used for sterilisation (e.g., surgical instruments/water).
4. Visible light