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.
Last updated
665 questions · page 11 of 34
- A. Constant amplitude
- B. Constant intensity
- C. Constant phase
- D. Same wavelength
Explanation: The correct option is C because In the context of interference patterns, a fringe represents a locus of points where the light waves are…
Correct answer: Constant phase- A. Decreases
- B. Increases
- C. Remains the same
- D. Sometimes increases and sometimes decreases
Explanation: The correct option is A because The refractive index generally decreases from the core to the periphery and is not known to vary…
Correct answer: Decreases- A. fo increases
- B. Both (a) and (c)
- C. fe decreases
- D. No change in fo and fe
Explanation: The correct option is B because For a large magnification of a telescope, both the focal length of the objective (fo ) and the focal…
Correct answer: Both (a) and (c)- A. Virtual
- B. Magnified
- C. Erect
- D. All
Explanation: The correct option is D because In the case of a simple microscope, the image formed is virtual, magnified, and erect.
Correct answer: All- A. Polarized
- B. Partially polarized
- C. Unpolarized
- D. Longitudinal waves
Explanation: The correct option is A because A Polaroid is a type of polarizing filter that selectively transmits light waves that are oscillating in a…
Correct answer: Polarized- A. Transmitters
- B. Receivers
- C. Repeaters
- D. All
Explanation: The correct option is C because In communication systems, light signals can weaken or degrade over long distances.
Correct answer: Repeaters- A. 20 diopters
- B. 5 diopters
- C. 1/20 diopters
- D. 1/5 diopters
Explanation: The correct option is B because The power of a lens in diopters is defined as the reciprocal of its focal length in meters.
Correct answer: 5 diopters- A. Longer wavelength light
- B. Shorter wavelength light
- C. Wavelength has no effect
- D. It depends only on the design of the microscope not on a light
Explanation: The resolving power of a microscope is determined by its ability to distinguish between two closely spaced objects.
Correct answer: Shorter wavelength light- A. Refractive index
- B. Frequency
- C. Amplitude
- D. All
Explanation: A is the right option because The speed of light in a material depends primarily on its refractive index, which is a measure of how much…
Correct answer: Refractive index- A. v=c
- B. v>c
- C. v<c
- D. v≥c
Explanation: C is the right option because The speed of light in a medium is always less than or equal to the speed of light in a vacuum (c).
Correct answer: v<c- A. Refractive index
- B. Angle of deviation of prism
- C. Wavelength
- D. All of these
Explanation: A spectrometer can be used to measure the wavelength of light, the refractive index of a prism, and the wavelengths of different colours -…
Correct answer: All of these- A. Small
- B. Infinity
- C. Large
- D. Of intermediate value
Explanation: A is the right option because To achieve a large magnification in a telescope, the focal length of the eyepiece (fe ) should be small.
Correct answer: Small- A. Diffraction
- B. Refraction
- C. Reflection
- D. Scattering and absorption
Explanation: D is the right option because Power loss in optical fibers primarily occurs due to scattering and absorption of light as it propagates…
Correct answer: Scattering and absorption- A. 80%
- B. 60%
- C. 50%
- D. 40%
Explanation: C is the right option because A perfect polarizer can reduce the intensity of unpolarized light by half (50%).
Correct answer: 50%- A. Orthogonal
- B. Parallel
- C. Non-existent
- D. Orthogonal and parallel
Explanation: A is the right option because The planes of vibration and polarization are orthogonal to each other.
Correct answer: Orthogonal- A. They should keep wearing their spectacles
- B. They should take off their spectacles.
- C. They may either put on their spectacles or take them off; it makes no difference.
- D. They cannot use the microscope at all.
Explanation: C is the right option because People wearing spectacles can work with a microscope either with or without their spectacles.
Correct answer: They may either put on their spectacles or take them off; it makes no difference.- A. Increasing the focal length of the eyepiece.
- B. Increasing the distance of the object.
- C. Fitting an eyepiece of low power.
- D. Fitting an eyepiece of high power.
Explanation: D is the right option because The magnifying power of a telescope is directly related to the power of the eyepiece.
Correct answer: Fitting an eyepiece of high power.- A. The focal length of lens used for observation
- B. The number of half period zones that superpose at the point
- C. The square of the sum of the number of half period zones
- D. The thickness of the obstacle
Explanation: The image depicts Fresnel diffraction, which occurs when light diffracts around the edges of an obstacle.
Correct answer: The number of half period zones that superpose at the point- A. a source
- B. a point source
- C. an extended source
- D. none of these
Explanation: These are surfaces of constant phase (points in a wave where the wave is in the same state) that originate from a point source.
Correct answer: a point source- A. Suffers no phase change.
- B. Undergoes a phase change of 180°.
- C. Undergoes a phase change of 270°.
- D. Undergoes a phase change of 90°.
Explanation: When light traveling in a rare (less dense) medium is reflected from a denser medium, the reflected light undergoes a phase change of 180…
Correct answer: Undergoes a phase change of 180°.