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📘 Study MCQs
Q1. What is the name of the transparent front part of the eye that protects it and allows light to enter?
• Retina
• Iris
• Cornea
• Pupil
Answer: Cornea
The cornea is the clear, dome-shaped front surface of the eye. It acts as a protective window and helps focus light entering the eye.
Q2. Which part of the eye controls the amount of light entering through the pupil?
• Lens
• Cornea
• Retina
• Iris
Answer: Iris
The iris is the coloured part of the eye surrounding the pupil. It contains muscles that adjust the pupil’s size to control light entry.
Q3. Where is the image formed in a human eye?
• Cornea
• Iris
• Retina
• Lens
Answer: Retina
The retina is the light-sensitive layer at the back of the eye. It receives light and converts it into signals sent to the brain, forming the image.
Q4. What is the function of the eye lens?
• To control pupil size
• To send signals to the brain
• To focus light onto the retina
• To give the eye its colour
Answer: To focus light onto the retina
The lens is a transparent, flexible structure located behind the iris. It fine-tunes focus by changing shape to direct light precisely onto the retina.
Q5. The ability of the eye lens to change its focal length is called?
• Persistence of vision
• Power of accommodation
• Visual acuity
• Refraction
Answer: Power of accommodation
The power of accommodation is the eye’s ability to adjust the curvature (and thus focal length) of the lens to see objects clearly at different distances.
Q6. Which muscles are responsible for changing the shape of the eye lens?
• Iris muscles
• Optic muscles
• Ciliary muscles
• Rectus muscles
Answer: Ciliary muscles
The ciliary muscles are attached to the lens by suspensory ligaments. When they contract or relax, they change the lens’s shape for focusing.
Q7. For a normal adult eye, what is the approximate least distance of distinct vision?
• 25 meters
• 25 centimeters
• 50 centimeters
• 100 centimeters
Answer: 25 centimeters
This is the minimum distance at which a normal eye can see an object clearly without strain. It is about 25 cm.
Q8. When we look at a distant object, what happens to the ciliary muscles and the lens?
• Muscles relax, lens becomes thin
• Muscles contract, lens becomes thick
• Muscles relax, lens becomes thick
• Muscles contract, lens becomes thin
Answer: Muscles relax, lens becomes thin
For distant vision, ciliary muscles relax. This pulls the suspensory ligaments tight, making the lens thin and less converging, increasing its focal length.
Q9. A major advantage of having two eyes instead of one is better?
• Colour vision in bright light
• Ability to see in the dark
• Judgment of distance and depth (3D vision)
• Ability to see moving objects
Answer: Judgment of distance and depth (3D vision)
Two eyes provide two slightly different images (from different angles). The brain combines them to give a three-dimensional perception and better judgment of depth.
Q10. Having two eyes also increases the?
• Intensity of light entering
• Field of view
• Size of the image formed
• Speed of vision
Answer: Field of view
With two eyes placed apart, we can see a wider area (field of view) without moving our head, helping in detecting surroundings better.
Q11. Which common eye defect is also known as nearsightedness?
• Hypermetropia
• Presbyopia
• Myopia
• Astigmatism
Answer: Myopia
In myopia, a person can see nearby objects clearly but cannot see distant objects distinctly. The image forms in front of the retina.
Q12. What is the main cause of myopia?
• Shortening of the eyeball
• Weakening of ciliary muscles
• Elongation of the eyeball or excessive curvature of the lens
• Hardening of the lens
Answer: Elongation of the eyeball or excessive curvature of the lens
Due to these reasons, the focal length of the eye lens decreases, or the eyeball is too long. Light from distant objects converges too soon, in front of the retina.
Q13. What type of lens is used to correct myopia?
• Convex lens
• Concave lens
• Cylindrical lens
• Bifocal lens
Answer: Concave lens
A concave lens is diverging. It diverges the incoming light rays slightly before they enter the eye, helping the image to form correctly on the retina.
Q14. Which common eye defect is also known as farsightedness?
• Myopia
• Hypermetropia
• Presbyopia
• Cataract
Answer: Hypermetropia
In hypermetropia, a person can see distant objects clearly but cannot see nearby objects distinctly. The image forms behind the retina.
Q15. What is the main cause of hypermetropia?
• Elongation of the eyeball
• Shortening of the eyeball or flattening of the eye lens
• Weakening of ciliary muscles
• Clouding of the lens
Answer: Shortening of the eyeball or flattening of the eye lens
Due to these reasons, the focal length of the eye lens increases, or the eyeball is too short. Light from nearby objects converges too late, behind the retina.
Q16. What type of lens is used to correct hypermetropia?
• Concave lens
• Convex lens
• Plano-concave lens
• Bifocal lens
Answer: Convex lens
A convex lens is converging. It provides additional convergence to the incoming light rays, helping the image to form correctly on the retina.
Q17. The age-related defect where the eye gradually loses its power of accommodation is called?
• Myopia
• Hypermetropia
• Presbyopia
• Astigmatism
Answer: Presbyopia
Presbyopia usually occurs in old age. The ciliary muscles weaken, and the eye lens becomes less flexible and harder, reducing its ability to change shape.
Q18. How is presbyopia commonly corrected?
• Using concave lenses only
• Using convex lenses only
• Using bifocal lenses
• Using cylindrical lenses
Answer: Using bifocal lenses
Bifocal lenses have two parts: the upper part (usually concave or plain) for distant vision and the lower part (convex) for near vision like reading.
Q19. What is the name of the phenomenon where white light splits into its component colours?
• Reflection
• Refraction
• Dispersion
• Scattering
Answer: Dispersion
Dispersion is the splitting of white light into its seven constituent colours (VIBGYOR) when it passes through a transparent medium like a prism.
Q20. Which optical element is typically used to demonstrate dispersion?
• Concave mirror
• Convex lens
• Rectangular glass slab
• Glass prism
Answer: Glass prism
A glass prism has a triangular cross-section. When a beam of white light passes through it, it refracts twice and disperses into a spectrum.
Q21. When white light passes through a prism, which colour deviates the least?
• Violet
• Blue
• Green
• Red
Answer: Red
Different colours have different wavelengths. Red light has the longest wavelength and bends (deviates) the least when refracted by the prism.
Q22. When white light passes through a prism, which colour deviates the most?
• Red
• Yellow
• Green
• Violet
Answer: Violet
Violet light has the shortest wavelength and bends (deviates) the most when refracted by the prism.
Q23. The band of colours obtained after dispersion of white light is called a?
• Light band
• Rainbow
• Reflection band
• Spectrum
Answer: Spectrum
The ordered arrangement of the coloured bands (Violet, Indigo, Blue, Green, Yellow, Orange, Red) is called the spectrum of white light.
Q24. What happens when the ciliary muscles contract?
• Lens becomes thin for distant vision
• Lens becomes thick for near vision
• Pupil becomes smaller
• Pupil becomes larger
Answer: Lens becomes thick for near vision
When ciliary muscles contract, the suspensory ligaments become loose. This allows the elastic lens to become more rounded and thick, increasing its converging power for nearby objects.
Q25. What is the role of the optic nerve?
• To focus light
• To control pupil size
• To carry signals from the retina to the brain
• To change lens shape
Answer: To carry signals from the retina to the brain
The retina converts light images into electrical signals. The optic nerve acts as a cable, transmitting these signals to the visual cortex of the brain for interpretation.
Q26. The small, central area of the retina with the sharpest vision is called the?
• Blind spot
• Optic nerve
• Fovea or yellow spot
• Choroid
Answer: Fovea or yellow spot
The fovea has the highest concentration of cone cells (responsible for colour and detail vision). When we look directly at an object, its image falls here for the clearest vision.
Q27. The point where the optic nerve leaves the eye is called the? It has no photoreceptor cells.
• Macula
• Fovea
• Pupil
• Blind spot
Answer: Blind spot
At the blind spot, the optic nerve connects to the retina. Since there are no rods or cones here, images falling on this spot are not seen.
Q28. What are the photoreceptor cells sensitive to dim light called?
• Cones
• Rods
• Optic nerves
• Ciliary cells
Answer: Rods
Rod cells are sensitive to low light levels and help us see in dim light (night vision). They do not detect colour.
Q29. What are the photoreceptor cells responsible for colour vision called?
• Rods
• Cones
• Ganglion cells
• Bipolar cells
Answer: Cones
Cone cells function best in bright light and are responsible for detecting colours and fine details.
Q30. The persistence of an image on the retina for about 1/16th of a second after removal of the object is called?
• Power of accommodation
• Persistence of vision
• Visual persistence
• Refractive memory
Answer: Persistence of vision
This is why we perceive motion pictures (movies) as continuous movement. The brain retains one image briefly as the next one appears.
Q31. In a myopic eye, the image of a distant object is formed:
• On the retina
• Behind the retina
• In front of the retina
• No image is formed
Answer: In front of the retina
Due to excessive converging power or long eyeball, light from distant objects focuses before it reaches the retina, causing blurriness.
Q32. The far point of a myopic eye is:
• At infinity
• Closer than infinity
• Farther than infinity
• At the near point
Answer: Closer than infinity
A myopic person cannot see objects beyond a certain distance clearly. The farthest point they can see clearly is at a finite distance, closer than infinity.
Q33. In a hypermetropic eye, the image of a nearby object is formed:
• On the retina
• Behind the retina
• In front of the retina
• Beside the retina
Answer: Behind the retina
Due to insufficient converging power or short eyeball, light from nearby objects focuses behind the retina, causing blurriness.
Q34. The near point of a hypermetropic eye is:
• At 25 cm
• More than 25 cm away
• Less than 25 cm away
• At infinity
Answer: More than 25 cm away
A hypermetropic person cannot see objects clearly at the normal near point (25 cm). Their near point is farther away.
Q35. The power of a lens is measured in units called:
• Meter (m)
• Centimeter (cm)
• Watt (W)
• Dioptre (D)
Answer: Dioptre (D)
The power (P) of a lens is the reciprocal of its focal length (f in meters): P = 1/f. The SI unit is dioptre.
Q36. A concave lens has a power that is:
• Positive
• Negative
• Zero
• Variable
Answer: Negative
Since a concave lens has a negative focal length (diverging), its power is expressed as a negative value (e.g., -2 D).
Q37. A convex lens has a power that is:
• Positive
• Negative
• Zero
• Variable
Answer: Positive
Since a convex lens has a positive focal length (converging), its power is expressed as a positive value (e.g., +3 D).
Q38. What is the white, tough outer layer of the eyeball called?
• Cornea
• Choroid
• Retina
• Sclera
Answer: Sclera
The sclera is the white part of the eye. It is a tough, fibrous layer that protects the inner parts and maintains the shape of the eyeball.
Q39. The middle layer of the eye, which contains blood vessels, is called the:
• Retina
• Sclera
• Choroid
• Cornea
Answer: Choroid
The choroid lies between the sclera and retina. It is dark (to prevent internal reflection) and supplies nutrients to the eye.
Q40. The splitting of white light into colours occurs because different colours have different:
• Intensities
• Speeds in a medium (like glass)
• Sources
• All of the above
Answer: Speeds in a medium (like glass)
In a medium like glass, violet light travels slower than red light. This difference in speed causes different amounts of bending (refraction), leading to dispersion.
Q41. A person uses spectacles with concave lenses. What is the defect of vision?
• Hypermetropia
• Presbyopia
• Myopia
• Astigmatism
Answer: Myopia
Concave lenses are used to correct myopia (nearsightedness) by diverging light rays before they enter the eye.
Q42. A person uses spectacles with convex lenses. What could be the defect of vision?
• Myopia
• Hypermetropia or Presbyopia
• Only Myopia
• Only Presbyopia
Answer: Hypermetropia or Presbyopia
Convex lenses are used to correct both hypermetropia (farsightedness) and the near-vision part of presbyopia by providing additional convergence.
Q43. The ability of the eye to see objects both near and far is due to the:
• Variable size of the pupil
• Movement of the eyeball
• Variable focal length of the lens (accommodation)
• Curvature of the cornea
Answer: Variable focal length of the lens (accommodation)
The eye’s lens changes its shape and thus its focal length, allowing it to focus on objects at various distances clearly.
Q44. The fluid present between the cornea and the lens is called:
• Vitreous humour
• Aqueous humour
• Tears
• Blood plasma
Answer: Aqueous humour
The aqueous humour is a watery, transparent fluid. It nourishes the cornea and lens and helps maintain the shape of the front part of the eye.
Q45. The phenomenon of bending of light when it goes from one medium to another is called:
• Reflection
• Refraction
• Dispersion
• Scattering
Answer: Refraction
Refraction is the change in direction (bending) of a light wave when it passes from one transparent medium to another with a different density (e.g., air to glass).
Q46. In the human eye, refraction of light mainly occurs at the:
• Retina and lens
• Cornea and lens
• Iris and pupil
• Optic nerve and retina
Answer: Cornea and lens
The greatest amount of refraction (bending) occurs when light enters the eye at the air-cornea interface. The lens provides the final fine-tuning of focus.
Q47. The far point of a normal eye is:
• 25 cm
• 100 cm
• 1 meter
• Infinity
Answer: Infinity
A normal eye can focus on objects that are very far away (effectively at infinity) when the ciliary muscles are fully relaxed and the lens is at its thinnest.
Q48. Which part of the eye is primarily responsible for the eye’s colour (e.g., blue, brown)?
• Cornea
• Retina
• Iris
• Choroid
Answer: Iris
The colour of the eye is determined by the amount and type of pigment in the iris. Brown eyes have more melanin, blue eyes have less.
Q49. What happens to the pupil in bright light?
• It expands to let in more light
• It contracts to let in less light
• It changes colour
• It disappears
Answer: It contracts to let in less light
In bright light, the circular muscles of the iris contract, reducing the size of the pupil. This protects the retina from excessive light.
Q50. What happens to the pupil in dim light?
• It contracts
• It expands
• It remains the same size
• It becomes square
Answer: It expands
In dim light, the radial muscles of the iris contract, enlarging the pupil. This allows more light to enter the eye to improve vision.