Question

The absolute refractive index of air is 1.0003 and the wavelength of yellow light in vacuum is 6000 Ã…. Find the thickness of air column which will have one more wavelength of the yellow light than in the same thickness of vacuum.

Solution

Correct option is

2mm

 

The wavelength of yellow light in vacuum is  and that in air is 

Let p be the number of waves in a thickness t of vacuum and p + 1 in the same thickness t of air. Then   

            

from these two equations, we have 

            

SIMILAR QUESTIONS

Q1

A wave has a speed of 330 metre/second and frequency 500 hertz. The phase difference between two adjacent points is π/3 radian. What will be the path difference between them? 

Q2

The equation of a simple harmonic wave is y1 = 0.40 sin (314 t – 1.57 x) meter, and that of another similar wave is y2 = 0.20 sin (314t – 1.57x + 1.57) meter. Find the phase difference between these two waves and the ratio of their intensities. 

Q3

In the figure given below is shown displacement-distance (y – x) graph of a transverse wave travelling along a string at the instant t = 0.25 s. At the instant t = 0, the end A of the string was in the mean position. Find out: (i) Frequency, wave-length and velocity of the wave, (ii) Equation of the wave, (iii) Displacement of B at the instant t = 1 second.

                                               

Q4

A transverse harmonic wave is travelling on a string with a speed of 25 m/s. A particle on the string has maximum velocity and maximum acceleration 4 m/s and 100 m/s2 respectively. What is the waveform?

Q5

A wave whose amplitude is 0.07m and frequency is 400 hertz travels in a medium with a velocity of 300 m/s. Determine the displacement equation of oscillation at a distance x metre from the source due to this wave.

Q6

What do you know about the speed of red and blue light (i) In vacuum, (ii) In glass? The refraction index of glass for blue light is 1.665 and for red light is 1.645. (The speed of light in vacuum is ).

Q7

 

(a) The wavelength of a given light is 0.00006 cm. Express this wavelength in micron and in angstrom. 

(b) What will be its wavelength in water, if the refractive index of water be 4/3.

Q8

The wavelength of a given light in vacuum is 6400 Ã…. Calculate its wavelength in water. Refractive index of water is 4/3.  

Q9

A light-ray of 6000 Ã… wavelength travelling in vacuum enters a medium of refractive index 1.5. Find the speed and the wavelength of the ray in the medium. 

Q10

The number of waves in a 4-cm thick strip of glass is the same as in 5-cm water, when the same monochromatic light travels in them. If the refractive index of water be 4/3, what will be of glass?