NEET Wave Optics — Set 17

Question 1

What is the frequency of light with a wavelength of $ 460 \, \text{nm} $ in air, given the speed of light in air is $ 3.0 \times 10^8 \, \text{m/s} $?

Accepted Answer

Frequency $ \nu = \frac{c}{\lambda} $. $ \lambda = 4.6 \times 10^{-7} \, \text{m} $, $ c = 3.0 \times 10^8 \, \text{m/s} $. $ \nu = \frac{3.0 \times 10^8}{4.6 \times 10^{-7}} \approx 6.52 \times 10^{14} \, \text{Hz} $.

Question 2

What determines the intensity of light in the wave picture?

Accepted Answer

In the wave picture, intensity is proportional to the square of the amplitude of the wave.

Question 3

What is the speed of light in a medium with refractive index 1.8, given the speed in vacuum is $ 3.0 \times 10^8 \, \text{m/s} $?

Accepted Answer

Speed in a medium $ v = \frac{c}{n} $. Given $ n = 1.8 $, $ c = 3.0 \times 10^8 \, \text{m/s} $, $ v = \frac{3.0 \times 10^8}{1.8} \approx 1.67 \times 10^8 \, \text{m/s} $.

NEET Physics: Wave Optics — Practice Set 17

Q1. What is the frequency of light with a wavelength of \( 460 \, \text{nm} \) in air, given the speed of light in air is \( 3.0 \times 10^8 \, \text{m/s} \)?

Q2. What determines the intensity of light in the wave picture?

Q3. What is the speed of light in a medium with refractive index 1.8, given the speed in vacuum is \( 3.0 \times 10^8 \, \text{m/s} \)?

Q4. Why does the intensity of light transmitted through two polaroids become zero when their axes are at 90° to each other?

Q5. What is the refractive index of a medium if the speed of light in it is \( 2.5 \times 10^8 \, \text{m/s} \) and in vacuum is \( 3.0 \times 10^8 \, \text{m/s} \)?

Q6. What is the frequency of light with a wavelength of \( 680 \, \text{nm} \) in air, given the speed of light in air is \( 3.0 \times 10^8 \, \text{m/s} \)?

Q7. Why does the angle of refraction increase beyond 90° become impossible when light moves from a denser to a rarer medium?

Q8. What is the fringe width in a double-slit experiment if \( \lambda = 590 \, \text{nm} \), \( d = 0.25 \, \text{mm} \), and \( D = 1.2 \, \text{m} \)?

Q9. What ensures that light rays appear to travel in straight lines despite their wave nature?

Q10. What property of light waves is responsible for the redistribution of energy into bright and dark regions during diffraction?