NEET Wave Optics — Set 6

Question 1

What is the nature of light waves demonstrated by polarization?

Accepted Answer

Polarization shows that light waves are transverse, as only transverse waves can be polarized.

Question 2

What is the refractive index of a medium if the speed of light in it is $ 2.1 \times 10^8 \, \text{m/s} $ and in vacuum is $ 3.0 \times 10^8 \, \text{m/s} $?

Accepted Answer

Refractive index $ n = \frac{c}{v} $. $ c = 3.0 \times 10^8 \, \text{m/s} $, $ v = 2.1 \times 10^8 \, \text{m/s} $. $ n = \frac{3.0 \times 10^8}{2.1 \times 10^8} \approx 1.43 $.

Question 3

What happens to the refracted wavefront when light enters a medium where its speed increases?

Accepted Answer

When speed increases (e.g., from glass to air), the refracted wavefront bends away from the normal.

NEET Physics: Wave Optics — Practice Set 6

Q1. What is the nature of light waves demonstrated by polarization?

Q2. What is the refractive index of a medium if the speed of light in it is \( 2.1 \times 10^8 \, \text{m/s} \) and in vacuum is \( 3.0 \times 10^8 \, \text{m/s} \)?

Q3. What happens to the refracted wavefront when light enters a medium where its speed increases?

Q4. What is the phase difference corresponding to a path difference of \( 7\lambda/4 \) in a double-slit experiment?

Q5. What ensures that the laws of reflection hold true when derived using the wave model?

Q6. What is the refractive index of a medium if the critical angle for light passing into air is \( 48.6^\circ \)?

Q7. What is the angular position of the second minimum in a single-slit diffraction pattern if the slit width is \( 2.0 \, \mu\text{m} \) and the wavelength is \( 400 \, \text{nm} \)?

Q8. What is the speed of light in a medium with refractive index 1.35, given the speed in vacuum is \( 3.0 \times 10^8 \, \text{m/s} \)?

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

Q10. Why does the wave theory predict that light bends towards the normal when entering a medium where its speed is lower?