With light falling normally on a transparent diffraction grating `10mm` wide, it was found that the components of the yellow line of sodium `(589.0` and `589.6nm`) are resolved beginning with the fifth order of the spectrum. Evaluate: (a) the period of this grating, (b) what must be the width of the grating with the same period for a double `lambda = 460.0nm` whose components differ by `0.13nm` to be resolved in the third order of the spectrum.

With light falling normally on a transparent diffraction grating `10mm

1.	With light falling normally on a transparent diffraction grating `10mm` wide, it was found that the components of the yellow line of sodium `(589.0` and `589.6nm`) are resolved beginning with the fifth order of the spectrum. Evaluate: (a) the period of this grating, (b) what must be the width of the grating with the same period for a double `lambda = 460.0nm` whose components differ by `0.13nm` to be resolved in the third order of the spectrum.
Answer» Here `R = (lambda)/(delta lambda) = (589.3)/(0.6) = kN = 5N` so `N = (589.3)/(3) = (10^(-2))/(d)` `d = (3 xx 10^(-2))/(589.3)m = 0509mm` (b) To resolve a doublet with `lambda = 460.0nm` and `delta lambda = 0.13nm` in the thrid order we must have `N = (R )/(3) = (460)/(3 xx 0.13) = 1179` This means that the grating is `Nd = 1179 xx 0.0509 = 60.03mm` wide `= 6cm` wide.

Discussion

No Comment Found

Related InterviewSolutions

Red light of wavelength `6500 Å` from a distant source falls on a slit `0.50 mm` wide. Calculate the distance between first two dark bands on each side of central bright band in the diffraction pattern observed on a screen placed `1.8 m` from the slit.
The ratio of the intensity at the centre of a bright fringe to the intensity at a point one-quarter of the distance between two fringe from the centre is
The ratio of the intensity at the centre of a bright fringe to the intensity at a point one-quarter of the distance between two fringe from the centre isA. `2`B. `1//2`C. `4`D. `16`
Among the two interfering monochromatic sources A and B, A is ahead of B in phase by `66^@`. If the observation be taken from point P, such that `PB-PA=lambda//4`. Then the phase difference between the waves from A and B reaching P isA. `156^(@)`B. `140^(@)`C. `136^(@)`D. `126^(@)`
The radius of curvature of curved surface of a thin plano-convex lens is `10 cm` and the refractive index is `1.5`. If the plano surface is silvered, then the focal length will be.A. 15 cmB. 20 cmC. 5 cmD. 10 cm
Calculate the resolving power of a microscope with cone angle of light falling on the objective equal to `60^(@)`. Take `lambda = 600 nm mu` for air `= 1`.
The diameter of the pupil of human eye is about `2 mm`. Human eye is most sensitive to the wavelength `555 nm`. Find the limit of resolution of human eye.
Assume that light of wavelength `6000 Å` is coming from a star. What is the limit of resolution of a telescope whose objective has a diameter of 100 inch ? (NCERT Solved example)
A central fringe of interference pattern produced by light of wavelength `6000 Å` is shifted to the position of 5th bright fringe by introducing thin film of `mu = 1.5`. Calculate thickness of the film.
Laser light of wavelength `630 nm` incident on a pair of slits produces an interference pattern where bright fringes are separated by `8.1 mm`. Another light produces the interference pattern, where the bright fringes are separated by `7.2 mm`. Calculate the wavelength of second light.

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment