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Optics MCQs 2026

50 questions with detailed answers · 19 from past papers · 5 quiz batches available

📚 Physics Mcqs 📄 19 Past-Paper Qs ✓ Free · No Login Needed
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Read each question, think about the answer, then click Show Answer to reveal the correct option and explanation. Load 10 at a time so it stays manageable — perfect for one-topic study sessions on the bus or during a break.

Page 1 of 1 Questions 1–10 of 50
  1. Q1 Past Paper · PPSC/FPSC/NTS medium

    The critical angle is the angle of incidence in the denser medium for which the angle of refraction is

    1. A Zero degrees
    2. B 45 degrees
    3. C 90 degrees
    4. D 180 degrees
    💡 Explanation:

    The critical angle is defined as the angle of incidence at which the refracted ray grazes along the boundary at 90 degrees.

  2. Q2 Past Paper · PPSC/FPSC/NTS medium

    Optical fibers transmit light signals over long distances using the principle of

    1. A Total internal reflection
    2. B Simple reflection
    3. C Refraction only
    4. D Diffraction
    💡 Explanation:

    Optical fibers guide light along their length through repeated total internal reflection at the core-cladding boundary.

  3. Q3 medium

    The mirage effect seen on hot roads is caused by

    1. A Total internal reflection in air layers
    2. B Diffraction of sunlight
    3. C Refraction of light through layers of air with varying density
    4. D Polarization of light
    💡 Explanation:

    A mirage occurs due to refraction and total internal reflection as light passes through air layers of gradually varying temperature and density.

  4. Q4 medium

    The natural phenomenon in which sunlight is dispersed by water droplets to form a rainbow involves both

    1. A Reflection and polarization only
    2. B Diffraction and interference only
    3. C Refraction and total internal reflection
    4. D Absorption and scattering only
    💡 Explanation:

    A rainbow forms when sunlight refracts entering a water droplet, undergoes total internal reflection inside it, and refracts again on exit, dispersing into colors.

  5. Q5 Past Paper · PPSC/FPSC/NTS medium

    The phenomenon responsible for the blue color of the sky is

    1. A Rayleigh scattering of sunlight
    2. B Total internal reflection
    3. C Dispersion by clouds
    4. D Polarization of sunlight
    💡 Explanation:

    Rayleigh scattering causes shorter blue wavelengths to scatter more strongly than other colors by atmospheric gas molecules, making the sky appear blue.

  6. Q6 Past Paper · PPSC/FPSC/NTS medium

    Snell's law relates the angle of incidence and angle of refraction through the

    1. A Speed of light in vacuum only
    2. B Focal length
    3. C Angle of reflection
    4. D Refractive indices of the two media
    💡 Explanation:

    Snell's law, n1 sin(theta1) = n2 sin(theta2), relates the angles of incidence and refraction to the refractive indices of the two media.

  7. Q7 easy

    A plane mirror always forms an image that is

    1. A Real and inverted
    2. B Virtual, erect, and of the same size
    3. C Real and magnified
    4. D Virtual and diminished
    💡 Explanation:

    A plane mirror forms a virtual, erect image equal in size to the object, located as far behind the mirror as the object is in front.

  8. Q8 Past Paper · PPSC/FPSC/NTS easy

    The reversal of left and right in an image formed by a plane mirror is called

    1. A Refraction
    2. B Dispersion
    3. C Diffraction
    4. D Lateral inversion
    💡 Explanation:

    Lateral inversion is the apparent left-right reversal seen in images formed by plane mirrors.

  9. Q9 medium

    A concave mirror used for shaving or makeup produces an image that is

    1. A Always real and inverted
    2. B Always diminished
    3. C Always virtual and diminished
    4. D Virtual, erect, and magnified when the object is close
    💡 Explanation:

    When an object is placed within the focal length of a concave mirror, it produces a virtual, erect, and magnified image.

  10. Q10 Past Paper · PPSC/FPSC/NTS medium

    The mirror formula relating object distance (u), image distance (v), and focal length (f) is

    1. A f = u + v
    2. B 1/f = 1/v + 1/u
    3. C f = uv
    4. D 1/f = u + v
    💡 Explanation:

    The standard mirror formula is 1/f = 1/v + 1/u, applicable to both concave and convex mirrors with sign conventions.

  11. Q11 medium

    The focal length of a plane mirror is

    1. A Infinite
    2. B Zero
    3. C Equal to radius of curvature
    4. D Negative
    💡 Explanation:

    A plane mirror has zero curvature, so its radius of curvature and focal length are both considered infinite.

  12. Q12 Past Paper · PPSC/FPSC/NTS medium

    The relationship between focal length (f) and radius of curvature (R) of a spherical mirror is

    1. A f = 2R
    2. B f = R/2
    3. C f = R
    4. D f = R^2
    💡 Explanation:

    For a spherical mirror, the focal length is half the radius of curvature: f = R/2.

  13. Q13 Past Paper · PPSC/FPSC/NTS medium

    Convex mirrors are used as rear-view/side mirrors in vehicles mainly because they

    1. A Form real, inverted images
    2. B Magnify the image
    3. C Absorb glare
    4. D Provide a wider field of view
    💡 Explanation:

    Convex mirrors always form a diminished, upright virtual image, allowing a wider field of view than a plane mirror of the same size.

  14. Q14 Past Paper · PPSC/FPSC/NTS medium

    The color that bends the least when passing through a prism is

    1. A Red
    2. B Violet
    3. C Blue
    4. D Indigo
    💡 Explanation:

    Red light has the longest wavelength among visible colors and the lowest refractive index, so it bends the least.

  15. Q15 easy

    The phenomenon in which white light splits into its component colors while passing through a prism is called

    1. A Reflection
    2. B Polarization
    3. C Dispersion
    4. D Interference
    💡 Explanation:

    Dispersion occurs because different colors (wavelengths) of light refract by different amounts through the prism.

  16. Q16 Past Paper · PPSC/FPSC/NTS medium

    The color that bends the most when white light passes through a prism is

    1. A Violet
    2. B Red
    3. C Green
    4. D Orange
    💡 Explanation:

    Violet light has the shortest wavelength among visible colors and hence the highest refractive index, causing it to bend the most.

  17. Q17 Past Paper · PPSC/FPSC/NTS medium

    The correct order of colors in the visible spectrum from longest to shortest wavelength is

    1. A Violet to red
    2. B Blue, green, red, violet
    3. C Green to violet
    4. D Red, orange, yellow, green, blue, indigo, violet
    💡 Explanation:

    Visible light spectrum arranged from longest to shortest wavelength follows red, orange, yellow, green, blue, indigo, violet (ROYGBIV).

  18. Q18 Past Paper · PPSC/FPSC/NTS easy

    The angle of incidence equals the angle of reflection according to

    1. A Snell's law
    2. B Law of reflection
    3. C Law of refraction
    4. D Newton's law
    💡 Explanation:

    The law of reflection states the angle of incidence equals the angle of reflection, both measured from the normal.

  19. Q19 medium

    The reddish color of the sky at sunset is mainly due to

    1. A Total internal reflection
    2. B Scattering removing blue light, leaving longer wavelengths dominant
    3. C Dispersion inside water droplets
    4. D Absorption of red light
    💡 Explanation:

    At sunset, sunlight travels a longer path through the atmosphere, scattering away most blue light, so red and orange wavelengths dominate.

  20. Q20 Past Paper · PPSC/FPSC/NTS medium

    The bending of light when it enters from a denser medium to a rarer medium at an angle greater than the critical angle results in

    1. A Total internal reflection
    2. B Simple refraction
    3. C Diffraction
    4. D Dispersion
    💡 Explanation:

    If the angle of incidence in the denser medium exceeds the critical angle, all light is reflected back, a phenomenon called total internal reflection.

  21. Q21 Past Paper · PPSC/FPSC/NTS medium

    The SI unit of power of a lens is the

    1. A Watt
    2. B Diopter
    3. C Joule
    4. D Candela
    💡 Explanation:

    Lens power is measured in diopters (D), where 1 diopter equals the power of a lens with a 1-meter focal length.

  22. Q22 medium

    Endoscopes used in medical examinations rely mainly on

    1. A Concave mirrors
    2. B Convex lenses only
    3. C Dispersion of light
    4. D Optical fibers using total internal reflection
    💡 Explanation:

    Endoscopes use bundles of optical fibers that transmit light and images via total internal reflection into and out of the body.

  23. Q23 hard

    Young's double-slit experiment demonstrated which property of light

    1. A Rectilinear propagation
    2. B Total internal reflection
    3. C Dispersion
    4. D Interference and wave nature of light
    💡 Explanation:

    Young's double-slit experiment produced interference fringes, providing strong evidence for the wave nature of light.

  24. Q24 medium

    A periscope, used to see over obstacles, commonly works using

    1. A A pair of convex lenses
    2. B A concave lens and a mirror
    3. C Two plane mirrors set at 45 degrees
    4. D A prism only for dispersion
    💡 Explanation:

    A periscope commonly uses two plane mirrors (or prisms) inclined at 45 degrees to redirect light around obstacles.

  25. Q25 easy

    Real images can be formed on a screen because they are produced by

    1. A Virtual convergence of rays behind the mirror or lens
    2. B Imagination of the observer
    3. C Actual convergence of light rays
    4. D Divergent rays that appear to meet
    💡 Explanation:

    A real image forms where light rays actually converge and can be captured on a screen, unlike a virtual image.

  26. Q26 medium

    The bending of light around the edges of an obstacle or aperture is called

    1. A Diffraction
    2. B Reflection
    3. C Refraction
    4. D Polarization
    💡 Explanation:

    Diffraction is the spreading and bending of waves as they pass around obstacles or through narrow openings.

  27. Q27 hard

    Diffraction effects become most noticeable when the size of the obstacle or slit is

    1. A Much larger than the wavelength of light
    2. B Comparable to the wavelength of light
    3. C Infinite
    4. D Unrelated to wavelength
    💡 Explanation:

    Diffraction effects are prominent when the obstacle or aperture size is comparable to or smaller than the wavelength of the wave.

  28. Q28 medium

    The phenomenon in which light waves restrict their vibrations to a single plane is called

    1. A Polarization
    2. B Diffraction
    3. C Dispersion
    4. D Interference
    💡 Explanation:

    Polarization restricts the oscillation of light's electric field vector to a single plane, filtering out other orientations.

  29. Q29 medium

    The power of a lens is defined as

    1. A The product of focal length and refractive index
    2. B The square of the focal length
    3. C The reciprocal of the focal length in meters
    4. D The refractive index divided by focal length
    💡 Explanation:

    Lens power (in diopters) equals 1 divided by the focal length expressed in meters.

  30. Q30 Past Paper · PPSC/FPSC/NTS medium

    The lens formula relating object distance (u), image distance (v), and focal length (f) is

    1. A 1/f = 1/v - 1/u
    2. B 1/f = 1/v + 1/u
    3. C f = u - v
    4. D f = uv
    💡 Explanation:

    For thin lenses using the Cartesian sign convention, the lens formula is 1/f = 1/v - 1/u.

  31. Q31 easy

    A lens that is thinner at the center than at the edges is called

    1. A Convex lens
    2. B Concave lens
    3. C Biconvex lens
    4. D Plano-convex lens
    💡 Explanation:

    A concave (diverging) lens is thinner at the center and thicker at the edges.

  32. Q32 easy

    A lens that is thicker at the center than at the edges is called

    1. A Concave lens
    2. B Convex lens
    3. C Plano lens
    4. D Cylindrical lens only
    💡 Explanation:

    A convex (converging) lens is thicker at its center and thinner at the edges.

  33. Q33 medium

    Polaroid sunglasses reduce glare by using the principle of

    1. A Dispersion
    2. B Diffraction
    3. C Polarization
    4. D Total internal reflection
    💡 Explanation:

    Polaroid lenses selectively block horizontally polarized light, which is responsible for most glare from reflective surfaces.

  34. Q34 easy

    A virtual image cannot be obtained on a screen because it is formed by

    1. A The apparent, not actual, intersection of light rays
    2. B Light rays that physically converge
    3. C Diffraction of light
    4. D Complete absorption of light
    💡 Explanation:

    A virtual image forms where light rays only appear to diverge from, without physically meeting, so it cannot be projected onto a screen.

  35. Q35 hard

    Bright and dark fringes observed in an interference pattern result from

    1. A Refraction of light rays
    2. B Constructive and destructive interference of light waves
    3. C Total internal reflection
    4. D Dispersion of colors
    💡 Explanation:

    Bright fringes occur where waves interfere constructively, and dark fringes where they interfere destructively.

  36. Q36 easy

    White light is considered a mixture of

    1. A Only red and blue light
    2. B A single wavelength of light
    3. C Only primary colors red, green, and blue in equal parts always
    4. D Light of many different wavelengths (colors)
    💡 Explanation:

    White light is a combination of light of all visible wavelengths, which a prism can separate into its component colors.

  37. Q37 medium

    In a simple camera, the image formed on the film or sensor is

    1. A Virtual and erect
    2. B Real and inverted
    3. C Virtual and magnified
    4. D Real and erect
    💡 Explanation:

    A camera's convex lens forms a real, inverted, and diminished image on the film or sensor, similar to the human eye.

  38. Q38 easy

    An astronomical telescope is primarily used to view

    1. A Nearby small objects with high magnification
    2. B Only objects underwater
    3. C Distant celestial objects like stars and planets
    4. D Only microscopic organisms
    💡 Explanation:

    An astronomical telescope is designed to collect light from and magnify the image of distant celestial objects.

  39. Q39 medium

    A compound microscope uses which combination of lenses

    1. A Two concave lenses
    2. B An objective lens and an eyepiece lens, both convex
    3. C A convex mirror and a concave lens
    4. D A single convex lens
    💡 Explanation:

    A compound microscope uses two convex lenses, an objective lens near the object and an eyepiece lens near the eye, for higher magnification.

  40. Q40 easy

    A simple microscope uses a single

    1. A Concave mirror
    2. B Concave lens
    3. C Convex lens
    4. D Plane mirror
    💡 Explanation:

    A simple microscope (magnifying glass) uses a single convex lens to produce a magnified virtual image of a nearby object.

  41. Q41 easy

    The light-sensitive layer at the back of the human eye where images are formed is the

    1. A Cornea
    2. B Iris
    3. C Retina
    4. D Lens
    💡 Explanation:

    The retina contains photoreceptor cells (rods and cones) that convert light into nerve signals, forming the image.

  42. Q42 easy

    The part of the human eye responsible for controlling the amount of light entering it is the

    1. A Retina
    2. B Cornea
    3. C Iris
    4. D Optic nerve
    💡 Explanation:

    The iris adjusts the size of the pupil to regulate the amount of light entering the eye.

  43. Q43 medium

    Astigmatism, caused by an irregularly curved cornea or lens, is corrected using a

    1. A Convex lens
    2. B Concave lens
    3. C Bifocal lens
    4. D Cylindrical lens
    💡 Explanation:

    A cylindrical lens compensates for the uneven curvature of the cornea or lens that causes astigmatism.

  44. Q44 medium

    The age-related eye defect in which the eye lens loses its elasticity and near vision becomes difficult is called

    1. A Myopia
    2. B Astigmatism
    3. C Hypermetropia
    4. D Presbyopia
    💡 Explanation:

    Presbyopia is an age-related condition where the eye's lens becomes less flexible, reducing its ability to focus on nearby objects.

  45. Q45 Past Paper · PPSC/FPSC/NTS easy

    Hypermetropia (far-sightedness) is corrected using a

    1. A Convex lens
    2. B Concave lens
    3. C Cylindrical lens only
    4. D Plane mirror
    💡 Explanation:

    A convex (converging) lens helps focus incoming light sooner, bringing the image forward onto the retina.

  46. Q46 Past Paper · PPSC/FPSC/NTS easy

    The defect of vision in which a person cannot see nearby objects clearly is called

    1. A Hypermetropia
    2. B Myopia
    3. C Astigmatism
    4. D Presbyopia
    💡 Explanation:

    Hypermetropia (far-sightedness) occurs when the eyeball is too short or the lens too weak, focusing near images behind the retina.

  47. Q47 Past Paper · PPSC/FPSC/NTS easy

    Myopia (near-sightedness) is corrected using a

    1. A Convex lens
    2. B Plane mirror
    3. C Bifocal lens only
    4. D Concave lens
    💡 Explanation:

    A concave (diverging) lens diverges incoming light before it enters the eye, moving the focal point back onto the retina.

  48. Q48 medium

    Which of the following correctly orders regions of the electromagnetic spectrum by increasing wavelength

    1. A Gamma rays, radio waves, visible light
    2. B X-rays, radio waves, gamma rays
    3. C Visible light, gamma rays, X-rays
    4. D Gamma rays, X-rays, ultraviolet, visible light
    💡 Explanation:

    In order of increasing wavelength (decreasing frequency and energy): gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves, radio waves.

  49. Q49 Past Paper · PPSC/FPSC/NTS easy

    The defect of vision in which a person cannot see distant objects clearly is called

    1. A Hypermetropia
    2. B Presbyopia
    3. C Myopia
    4. D Astigmatism
    💡 Explanation:

    Myopia, or near-sightedness, occurs when the eyeball is too long or the lens too strong, focusing distant images in front of the retina.

  50. Q50 medium

    A converging (convex) lens has a power that is

    1. A Positive
    2. B Negative
    3. C Always zero
    4. D Undefined
    💡 Explanation:

    By convention, converging convex lenses are assigned a positive power, while diverging concave lenses have negative power.

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