Chapter 3: Wave Optics — Online MCQ Test
PHYSICS · CLASS 12 INTERMEDIATE 2 YEAR · Telangana State Board
Practice Chapter 3: Wave Optics with a free chapter-wise online MCQ test.
This chapter covers: Focusing on wave nature of light this chapter covers Huygens principle wave front propagation Young double slit experiment interference conditions diffraction patterns and polariza....
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Chapter 3: Wave Optics — Important Questions & Answers
According to Huygens' principle, every point on a wavefront acts as a source of new ____.
- A. particles
- B. secondary wavelets
- C. rays of light
- D. electrons
Answer: B. secondary wavelets
Huygens' principle states that each point on a wavefront gives rise to secondary wavelets, and the new wavefront is the envelope of these wavelets.
Huygens' principle states that each point on a wavefront gives rise to secondary wavelets, and the new wavefront is the envelope of these wavelets.
The phenomenon that proves the wave nature of light most directly is ____.
- A. reflection
- B. refraction
- C. interference
- D. dispersion
Answer: C. interference
Interference is a characteristic wave phenomenon and is strong evidence for the wave nature of light.
Interference is a characteristic wave phenomenon and is strong evidence for the wave nature of light.
In Young's double slit experiment, if the wavelength of light is increased, the fringe width will ____.
- A. decrease
- B. remain unchanged
- C. increase
- D. become zero
Answer: C. increase
Fringe width is directly proportional to wavelength. So an increase in wavelength increases the fringe width.
Fringe width is directly proportional to wavelength. So an increase in wavelength increases the fringe width.
Which of the following statements about interference is NOT correct?
- A. The two sources should be coherent
- B. The two sources should have the same frequency
- C. The interfering waves should have a constant phase difference
- D. The two sources must have equal intensities always
Answer: D. The two sources must have equal intensities always
Equal intensities are not necessary for interference, though they help in obtaining clearer fringes.
Equal intensities are not necessary for interference, though they help in obtaining clearer fringes.
A beam of light with intensity I0 is passed through three polaroids. The first and second have their transmission axes at 45° and the second and third at 45° again. The transmitted intensity is ____.
- A. I0/8
- B. I0/4
- C. I0/2
- D. 3I0/8
Answer: A. I0/8
After the first polaroid, intensity becomes I0/2. Each 45° step multiplies intensity by cos²45° = 1/2, giving I0/2 × 1/2 × 1/2 = I0/8.
After the first polaroid, intensity becomes I0/2. Each 45° step multiplies intensity by cos²45° = 1/2, giving I0/2 × 1/2 × 1/2 = I0/8.