Class 12 Physics MCQ Chapter 9 Ray Optics and Optical Instruments
Master the concepts of optics with our Class 12 Physics MCQ Chapter 9 Ray Optics and Optical Instruments English Medium study resource. This article contains a comprehensive collection of exam-oriented multiple-choice questions (MCQs) with answers, specially prepared for AHSEC Higher Secondary students.
The chapter Ray Optics and Optical Instruments is one of the most important units in Class 12 Physics. It covers fundamental topics such as reflection of light, refraction, total internal reflection, mirrors, lenses, prism, optical fibers, magnification, and the working principles of optical instruments like microscopes and telescopes. A strong understanding of these concepts is essential for both board examinations and competitive entrance tests.
All MCQs are based on the latest AHSEC syllabus and examination pattern, ensuring that students practice relevant and high-scoring questions. These objective questions are ideal for quick revision, self-assessment, and strengthening conceptual understanding. Regular practice will help students improve accuracy, develop problem-solving skills, and gain confidence in tackling Physics examinations.
Whether you are preparing for class tests, mock examinations, or the AHSEC Higher Secondary Final Examination, these Chapter 9 MCQ solutions will serve as an effective study companion for achieving excellent results.
PART II
Ray Optics and Optical Instruments
VSA & MCQ
I. Very Short Answer Questions
Q. What is ray optics?
Ans: Ray optics is the study of light propagation in terms of rays.
Q. What is reflection of light?
Ans: Bouncing back of light from a surface.
Q. State laws of reflection.
Ans: Angle of incidence equals angle of reflection; incident ray, reflected ray and normal lie in same plane.
Q. What is refraction?
Ans: Bending of light when it passes from one medium to another.
Q. State Snell’s law.
Ans: n₁ sinθ₁ = n₂ sinθ₂.
Q. What is refractive index?
Ans: n = c / v.
Q. What is absolute refractive index?
Ans: Refractive index with respect to vacuum.
Q. What is total internal reflection?
Ans: Complete reflection when light goes from denser to rarer medium beyond critical angle.
Q. What is critical angle?
Ans: Angle of incidence for which angle of refraction is 90°.
Q. What is mirror formula?
Ans: 1/f = 1/v + 1/u.
Q. What is magnification in mirror?
Ans: m = v / u.
Q. What is focal length?
Ans: Distance between pole and focus.
Q. What is power of lens?
Ans: P = 1/f (in meters).
Q. What is unit of power?
Ans: Dioptre (D).
Q. What is lens formula?
Ans: 1/f = 1/v − 1/u.
Q. What is magnification in lens?
Ans: m = v / u.
Q. What is optical fibre?
Ans: Device using total internal reflection to transmit light.
Q. What is dispersion?
Ans: Splitting of light into colors.
Q. What is prism?
Ans: Transparent optical element with triangular cross-section.
Q. What is angle of deviation?
Ans: Angle between incident and emergent ray.
Q. What is condition for minimum deviation?
Ans: Angle of incidence equals angle of emergence.
Q. What is spherical aberration?
Ans: Defect due to different focal points for different rays.
Q. What is coma?
Ans: Aberration causing comet-like images.
Q. What is astigmatism?
Ans: Image not focused at a point.
Q. What is simple microscope?
Ans: Single convex lens.
Q. What is magnifying power?
Ans: Ratio of image angle to object angle.
Q. What is compound microscope?
Ans: Uses objective and eyepiece lenses.
Q. What is telescope?
Ans: Instrument to view distant objects.
Q. What is resolving power?
Ans: Ability to distinguish close objects.
Q. What is limit of resolution?
Ans: Minimum distance between two distinguishable points.
II. Multiple Choice Questions
Q. Reflection law is:
(a) θi = θr
(b) θi ≠ θr
(c) θi > θr
(d) None
Ans: (a)
Q. Refraction occurs due to change in:
(a) Speed
(b) Frequency
(c) Wavelength only
(d) Direction only
Ans: (a)
Q. Refractive index is:
(a) c/v
(b) v/c
(c) c×v
(d) v²
Ans: (a)
Q. Total internal reflection occurs when:
(a) Denser to rarer
(b) Rarer to denser
(c) Equal media
(d) Vacuum
Ans: (a)
Q. Unit of power is:
(a) Watt
(b) Dioptre
(c) Joule
(d) Volt
Ans: (b)
Q. Mirror formula is:
(a) 1/f = 1/v + 1/u
(b) 1/f = 1/v − 1/u
(c) f = uv
(d) None
Ans: (a)
Q. Lens formula is:
(a) 1/f = 1/v − 1/u
(b) 1/f = 1/v + 1/u
(c) f = uv
(d) None
Ans: (a)
Q. Optical fibre uses:
(a) Reflection
(b) Refraction
(c) Total internal reflection
(d) Diffraction
Ans: (c)
Q. Prism causes:
(a) Reflection
(b) Dispersion
(c) Absorption
(d) Interference
Ans: (b)
Q. Telescope is used for:
(a) Near objects
(b) Distant objects
(c) Small objects
(d) Light
Ans: (b)
Q. Assertion: Light bends during refraction. Reason: Speed changes in different media.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Total internal reflection occurs only from denser to rarer medium. Reason: Critical angle exists only in this case.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Refractive index depends on medium. Reason: Speed of light varies.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Prism deviates light. Reason: Due to refraction at surfaces.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Optical fibre transmits light efficiently. Reason: Uses multiple reflections.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (b)
Q. Assertion: Telescope magnifies distant objects. Reason: Uses convex lens system.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
Q. Assertion: Dispersion occurs in prism. Reason: Different wavelengths refract differently.
(a) Both true, reason correct
(b) Both true, reason incorrect
(c) Assertion true, reason false
(d) Both false
Ans: (a)
