Light the Human Eye and the Colourful World (Class 10)

What this worksheet covers

This is an eighteen-question practice worksheet on light, the human eye and the colourful world for Class 10, written to the pattern of the SOF National Science Olympiad (NSO). It carries 24 marks and is designed to be attempted in 45 minutes, split across three sections — Scientific Reasoning, Applying What You Know and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on light, the human eye and the colourful world at Class 10 level
• Working accurately against a time limit, as the real paper demands
• Scientific Reasoning questions in the olympiad format
• Applying What You Know questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 18 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–15 carry 1 mark each. Questions 16–18 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Study every ray diagram and table carefully.

Sample questions from this worksheet

A preview of what's inside Light the Human Eye and the Colourful World (Class 10) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. According to the laws of reflection, the angle of incidence is _______ the angle of reflection.

   • AGreater than
   • BLess than
   • CEqual tocorrect
   • DTwice
   Solution: The angle of incidence is always equal to the angle of reflection, and the incident ray, the reflected ray and the normal all lie in one plane.

2. 2. The focal length of a convex lens is 50 cm. Its power is _______.

   • A+0.5 D
   • B+50 D
   • C−2 D
   • D+2 Dcorrect
   Solution: Convert the focal length to metres: 50 cm = 0.5 m. Then P = {1/0.5} = +2 D, positive because the lens is converging.

3. 3. Assertion (A): The sun appears reddish at sunrise and sunset.Reason (R): Near the horizon sunlight travels through a much greater thickness of atmosphere, so most of the blue light is scattered away before it reaches us.

   • ABoth A and R are true and R is the correct explanation of Acorrect
   • BBoth A and R are true but R is not the correct explanation of A
   • CA is true but R is false
   • DA is false but R is true
   Solution: At sunrise and sunset the light takes a long slanting path through the air. The short blue wavelengths are scattered out of that beam, leaving mainly the long red ones to reach the eye. Both statements are true and the second is exactly why the first happens, so R explains A.