MCQs on Waves Optics
Q1: Polarisation phenomenon explains which nature of light?
- Both transverse and longitudinal
Answer: (a) Transverse
Q2: A narrow slit is taken and a parallel beam of moving electrons is incident normally on it. At a larger distance from the slit, a fluorescent screen is placed. Which of the following statement is true if the size of the slit is further narrowed?
- The diffraction pattern cannot be observed on the screen
- The angular width of the central maxima of the diffraction pattern will increase
- The angular width of the central maxima of the diffraction pattern will decrease
- The angular width of the central maxima of the diffraction pattern remains the same
Answer: (c) The angular width of the central maxima of the diffraction pattern will decrease
Q3: How does the diffraction band of blue light look in comparison with the red light?
- No changes
- Diffraction pattern becomes narrower
- Diffraction pattern becomes broader
- Diffraction pattern disappears
Answer: (b) Diffraction pattern becomes narrower
Q4: Two coherent sources of light can be obtained from
- Two different lamps
- Two different lamps but of the same colour
- Two different lamps of the same colour and having the same colour
- None of these
Answer: (d) None of these
Q5: Which of the following phenomenon is not explained by Huygen’s wave theory?
- Photoelectric effect
Answer: (d) Photoelectric effect
Q6: What is the value of coherent time if L is the coherent length and c is the velocity of light?
Answer: (b) L/c
Q7: The ratio of the amplitude of the two sources producing interference 3 : 5, the ratio of intensities at maxima and minima is
Answer: (c) 16:1
Q8: The colours on the soap bubble is due to
Answer: (a) Interference
Q9: Which of the following statements indicates that light waves are transverse?
- Light waves can be polarised
- Light waves can show interference
- Light waves undergo diffraction
- They travel in the vacuum
Answer: (a) Light waves can be polarised
Q10: In Young’s double-slit experiment, the phase difference between the light waves reaching the third bright fringe from the central fringe will be (λ=6000 Å)