# CBSE Important Questions(3 Mark questions) for CBSE Class 10 Science Human Eye and Colourful World

QUESTIONS: (3Marks each)
Q1. Explain power of accommodation. Explain in brief the near and the far point of an eye and give their values.
Q2. How does the focal length of the eye lens change when we shift looking from a nearby object to a distance object?
Q3. Sometimes when we enter into a dark room from bright sunlight we are unable to see objects clearly. Why?
Q4. Define least distance of distinct vision. Give the value of least distance of distinct vision for a young adult with healthy eye.

Q5. What is cataract and how it can be corrected? Distinguish it from presbyopia.
Q6. What is a prism? Explain the term dispersion of light. Illustrate with a diagram the phenomenon of dispersion through it.
Q7. Draw a labeled ray diagram to show the formation of rainbow in the sky giving brief explanation of the phenomena involved at each stage. List two condition necessary to observe a rainbow.
Q8. (a) The sky appears dark to passengers flying in space. Why?
(b) Which component of white light is least scattered by fog or smoke? Explain.
Q9. The far point of a myopic person is 150 cm in front of the eye. Calculate the focal length and the power of a lens required to enable him to see distant objects clearly.
Q10. A person is able to see objects clearly only when these are lying at distance between 50 cm and 300 cm from his eye.
1. What kind of defect of vision is he suffering from?
2. What kind of lenses will he required to increase his range of vision from 25 cm to infinity? Explain.

### Practice Question

Question 1 Which among the following is not a base?
A) NaOH
B) $NH_4OH$
C) $C_2H_5OH$
D) KOH
Question 2 What is the minimum resistance which can be made using five resistors each of 1/2 Ohm?
A) 1/10 Ohm
B) 1/25 ohm
C) 10 ohm
D) 2 ohm
Question 3 Which of the following statement is incorrect? ?
A) For every hormone there is a gene
B) For production of every enzyme there is a gene
C) For every molecule of fat there is a gene
D) For every protein there is a gene