Which part of the human eye controls the amount of light entering it?
Difficulty: Medium
About this MCQ
This Medium Everyday Science MCQ checks one syllabus fact. Candidates use it for PPSC Lecturer practice.
The question is: “Which part of the human eye controls the amount of light entering it?”
The accepted answer is C. Iris. The iris is the coloured muscular diaphragm that adjusts the size of the pupil, thereby controlling how much light enters the eye.
- A. Retina
Why not A: The retina detects light and forms images; it does not control light entry.
- B. Cornea
Why not B: The cornea helps focus light but does not regulate its amount.
- C. Iris ✓
- D. Lens
Why not D: The lens focuses light onto the retina by changing shape.
Correct answer
C. Iris
Explanation
The iris is the coloured muscular diaphragm that adjusts the size of the pupil, thereby controlling how much light enters the eye.
Source: Human anatomy — eye structure
Tags: Biology, Human Body
Relevant exams: PPSC Lecturer
Submitted by: MCQsHub Editorial