NEET Wave Optics — Set 7

Question 1

Why is the backwave not observed in the reflection of light according to the wave model?

Accepted Answer

The wave model assumes the amplitude of secondary wavelets is zero in the backward direction, though this is an ad-hoc assumption later justified by advanced wave theory.

Question 2

What happens to the fringe width in a double-slit experiment if the distance between the slits and the screen is tripled?

Accepted Answer

Fringe width $ \beta = \frac{\lambda D}{d} $. If $ D $ is tripled, $ \beta $ triples.

Question 3

What characteristic of light waves allows polarization to occur, distinguishing them from sound waves?

Accepted Answer

Light waves are transverse, with electric fields oscillating perpendicular to the propagation direction, enabling polarization, unlike longitudinal sound waves.

NEET Physics: Wave Optics — Practice Set 7

Q1. Why is the backwave not observed in the reflection of light according to the wave model?

Q2. What happens to the fringe width in a double-slit experiment if the distance between the slits and the screen is tripled?

Q3. What characteristic of light waves allows polarization to occur, distinguishing them from sound waves?

Q4. What property of light ensures that the time taken from an object point to its image point is the same along any ray path in a lens system?

Q5. Why does light exhibit polarization only in specific directions when passing through a polaroid?

Q6. What happens to the fringe width in a double-slit experiment if both the slit separation and screen distance are doubled?

Q7. Why does the intensity of light remain unaffected by changes in its speed during refraction?

Q8. What happens to the fringe width in a double-slit experiment if the slit separation is reduced to one-third?

Q9. What is the path difference for the first dark fringe in a double-slit experiment?

Q10. What is the distance of the second bright fringe from the central maximum in a double-slit experiment if \( \lambda = 670 \, \text{nm} \), \( d = 0.6 \, \text{mm} \), and \( D = 1.8 \, \text{m} \)?