NEET Wave Optics — Set 14

Question 1

What is the condition for constructive interference in a double-slit experiment?

Accepted Answer

Constructive interference occurs when the path difference is an integer multiple of the wavelength, i.e., $ \Delta = n\lambda $, where $ n = 0, 1, 2, \ldots $.

Question 2

Why does the reflected wavefront from a plane surface maintain the same angle as the incident wavefront?

Accepted Answer

The wave model shows that secondary wavelets from the surface form a reflected wavefront where the angle of incidence equals the angle of reflection due to geometric symmetry.

Question 3

What property of light waves enables the formation of a stable interference pattern when split from a single source?

Accepted Answer

Coherence, or a fixed phase relationship, is maintained when light from one source is split, allowing constructive and destructive interference to form a stable pattern.

NEET Physics: Wave Optics — Practice Set 14

Q1. What is the condition for constructive interference in a double-slit experiment?

Q2. Why does the reflected wavefront from a plane surface maintain the same angle as the incident wavefront?

Q3. What property of light waves enables the formation of a stable interference pattern when split from a single source?

Q4. In a double-slit experiment, if \( \lambda = 450 \, \text{nm} \), \( d = 0.15 \, \text{mm} \), and \( D = 1.5 \, \text{m} \), what is the fringe width?

Q5. What is the frequency of light with a wavelength of \( 595 \, \text{nm} \) in air, given the speed of light in air is \( 3.0 \times 10^8 \, \text{m/s} \)?

Q6. What is the angular position of the first minimum in a single-slit diffraction pattern if the slit width is \( 10.0 \, \mu\text{m} \) and the wavelength is \( 500 \, \text{nm} \)?

Q7. Why does the interference pattern from two slits vanish if one slit is covered?

Q8. In a double-slit experiment, if \( \lambda = 510 \, \text{nm} \), \( d = 0.3 \, \text{mm} \), and \( D = 1.5 \, \text{m} \), what is the distance of the second bright fringe from the central maximum?

Q9. What is the condition for destructive interference in a double-slit experiment?

Q10. What is the intensity of light after passing through two polaroids with pass-axes at \( 75^\circ \), if the initial unpolarized intensity is \( I_0 \)?