Concepts Of Physics MCQ Edition [Volume 1]PhysicsOptical Instruments
The muscles of a normal eye experience the least strain when focusing on an object that is
Options
- Afar away from the eye
- Bvery close to the eye
- Cat about 1 m from the eye
- Dat about 25 cm from the eye
Correct answer
A. far away from the eye
Step-by-step solution
When a normal eye focuses on an object placed at infinity (far away), the ciliary muscles are completely relaxed. In this state, the focal length of the eye lens is at its maximum, and the eye is in an unaccommodated state. Conversely, when focusing on nearby objects, the ciliary muscles contract to increase the curvature of the lens, which causes strain. The maximum strain occurs when the object is at the near point (about 25 cm ). Thus, the muscles experience the least strain when the object is far away from the