Free Optics MCQs with Answers
665 Optics MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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665 questions · page 29 of 34
- A. Increases
- B. Decreases
- C. Remains the same
- D. None of these
Explanation: The energy of a photon is determined by its frequency, not by its speed.
Correct answer: Remains the same- A. Waves only
- B. Particles only
- C. Both waves and particles
- D. None of these
Explanation: The correct answer is that light behaves as both waves and particles. This is known as wave-particle duality, a fundamental concept in…
Correct answer: Both waves and particles- A. Zero
- B. 0.5 gram
- C. 1 gram
- D. 10 gram
Explanation: The rest mass of a photon is zero. Photons are unique because they are elementary particles that travel at the speed of light, as…
Correct answer: Zero- A. Wavelength
- B. Intensity
- C. Frequency
- D. None of these
Explanation: The energy of a photon is given by Planck's equation, E = hν, where E represents energy, h is Planck's constant, and ν (nu) is the…
Correct answer: Frequency- A. Interference
- B. Polarization
- C. Diffraction
- D. Reflection
Explanation: The correct answer is Polarization. Polarization filters light waves so that they oscillate in only one plane, which is evidence of their…
Correct answer: Polarization- A. Light has dual nature
- B. Light travels in straight line
- C. All points on a primary wavefront are sources of secondary wavelets
- D. None of these
Explanation: Huygen's principle is a method of analysis applied to problems of wave propagation both in the far field limit and in near field…
Correct answer: All points on a primary wavefront are sources of secondary wavelets- A. Homogenous
- B. Non-homogenous
- C. Vacuum
- D. None of these
Explanation: The correct answer is Homogenous. A homogenous medium has uniform properties throughout, meaning the speed of light remains constant in…
Correct answer: Homogenous- A. Plane wave front
- B. Spherical wave front
- C. Cylindrical wave front
- D. Rectangular wave front
Explanation: The correct answer is a spherical wave front. This is because a point source of light in a homogeneous medium emits light uniformly in all…
Correct answer: Spherical wave front- A. Cylindrical wave front
- B. Spherical wave front
- C. Plane wave front
- D. Elliptical wave front
Explanation: When light emanates from a point source, it initially forms spherical wave fronts.
Correct answer: Plane wave front- A. Locate the wave front
- B. Explain diffraction
- C. Explain interference
- D. Find the speed of light
Explanation: Huygen's principle is a fundamental concept in wave optics that helps determine the position and shape of wave fronts as they propagate…
Correct answer: Locate the wave front- A. 2d sin θ = ηλ
- B. d sin θ = mλ
- C. d sin θ = (m + 1/2)λ
- D. d sin θ = (m + 1)λ
Explanation: The correct answer is Option B: d sin θ = mλ.In Young's double-slit experiment, constructive interference occurs when the path difference…
Correct answer: d sin θ = mλ- A. y = m λ L / d
- B. y = m d L
- C. y = m L d / λ
- D. y = m d / L
Explanation: The correct formula for the positions of bright fringes in Young's double-slit experiment is y = m λ L / d.
Correct answer: y = m λ L / d- A. Wavelength
- B. Fringe spacing
- C. Half-wavelength
- D. Width of slit
Explanation: The correct answer is Option B: Fringe spacing. In Young's double slit experiment, the distance between two consecutive bright fringes or…
Correct answer: Fringe spacing- A. Frequency of light
- B. Intensity of light
- C. Amplitude of light
- D. Wavelength of light
Explanation: The Michelson interferometer is a device that splits a beam of light into two paths, reflects them back, and then recombines them to…
Correct answer: Wavelength of light- A. Diffraction
- B. Interference
- C. Polarization
- D. None of these
Explanation: The correct answer is interference. In a Michelson interferometer, light from a single source is split into two beams, which travel…
Correct answer: Interference- A. Ultra-violet rays
- B. Visible light
- C. Infra-red radiation
- D. Gamma rays
Explanation: Gamma rays have the highest frequency of all the electromagnetic waves.
Correct answer: Gamma rays- A. 10-10 cm
- B. 10-8 cm
- C. 10 m
- D. 1010 mm
Explanation: The correct answer is 10-8 cm because an Angstrom is a unit of length used to express very small distances, typically at the atomic scale.
Correct answer: 10-8 cm- A. Bright fringes are wider than dark fringes
- B. Dark fringes are wider than bright fringes
- C. Both dark and bright fringes are of equal width
- D. None of these
Explanation: In a typical interference pattern created by the overlapping of coherent light waves, both bright and dark fringes are formed due to…
Correct answer: Both dark and bright fringes are of equal width- A. 0.1 Å
- B. 000 Å
- C. 100 Å
- D. 1 Å
Explanation: X-rays are a form of electromagnetic radiation with very short wavelengths, typically around 1 Å (angstrom), which allows them to…
Correct answer: 1 Å- A. 90°
- B. 180°
- C. 60°
- D. 45°
Explanation: When a ray of light travels from a rarer medium (such as air) to a denser medium (such as glass), and it reflects off the surface of the…
Correct answer: 180°