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Chapter 7: Wave Optics — Online MCQ Test

PHYSICS · CLASS 12th · Tamil Nadu State Board
Practice Chapter 7: Wave Optics with a free chapter-wise online MCQ test. This chapter covers: Exploring light wave phenomena this chapter details Huygens principle interference diffraction and polarization. Students analyze Young double slit experiment resolving power and B.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 7: Wave Optics — Important Questions & Answers

According to Huygens' principle, every point on a wavefront acts as a source of what?
  • A. Particles of light
  • B. Secondary wavelets
  • C. Polarized rays
  • D. Interference fringes
Answer: B. Secondary wavelets
Huygens' principle states that each point on a wavefront behaves as a source of secondary wavelets, which helps explain wave propagation.
In Young's double slit experiment, the condition for constructive interference at a point is:
  • A. Path difference = (2n + 1)λ/2
  • B. Path difference = nλ
  • C. Path difference = λ/4
  • D. Path difference = (n + 1)λ
Answer: B. Path difference = nλ
Bright fringes are formed when the path difference between the two waves is an integral multiple of wavelength, i.e., nλ.
In Young's double slit experiment, if the slit separation is increased while all other factors remain constant, the fringe width will:
  • A. Increase
  • B. Decrease
  • C. Remain unchanged
  • D. Become zero
Answer: B. Decrease
Fringe width is inversely proportional to slit separation, so increasing slit separation reduces fringe width.
The central bright fringe in Young's double slit experiment is obtained because:
  • A. Path difference is λ
  • B. Path difference is zero
  • C. Path difference is λ/2
  • D. Waves undergo diffraction only
Answer: B. Path difference is zero
At the center of the screen, the two waves travel equal distances, so the path difference is zero and maximum intensity occurs.
The resolving power of a telescope depends mainly on:
  • A. Focal length of the objective only
  • B. Diameter of the objective lens and wavelength used
  • C. Eyepiece magnification only
  • D. Distance of the object only
Answer: B. Diameter of the objective lens and wavelength used
A larger objective aperture and shorter wavelength improve resolving power by reducing diffraction limitation.