Question 13 - MCQs from NCERT Exemplar - Chapter 11 Class 10 - Human Eye and Colourful World

The focal length of the eye lens increases when eye muscles

(a) are relaxed and lens becomes thinner

(b) contract and lens becomes thicker

(c) are relaxed and lens becomes thicker

(d) contract and lens becomes thinner

Answer

• Ciliary muscles stretch and relax to adjust the focal length of our eye lens. 
• The focal length increases when the muscles are relaxed and the lens becomes thinner.  
• The focal length decreases when the muscles are stretched and the lens becomes thicker.  

So, the correct answer is (a)