The D line in the spectrum of sodium is a doublet with wavelengths 589.0and589.6nm. Calculate the minimum number of lines needed in a grating that will resolve this doublet in the second-order spectrum.

Short Answer

Expert verified

The minimum number of lines needed in the grating, to resolve the douplet, is 491.

Step by step solution

01

The resolving power

It is known the resolving power of a grating is given by-

R=Nm=λavgλ

where Nis the number of rulings in the grating and mis the order of the linesλavg, is the average of wavelengths, and λis the wavelength difference.
02

Given Data

The wavelength of the sodium doublet is - 589.0nmand589.6nm

03

The number of rulings

The resolving power of the grating is given as-

Nm=λavgΔλ

From the given values in the question, we have

N×2=589.0nm+589.6nm2589.6nm-589.0nmN×2=1178.6nm20.6nm

On solving further,

N=1178.6nm0.6nm×2×2N=491

Thus, the minimum number of lines needed in the grating is 491.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The two headlights of an approaching automobile are 1.4m apart. At what (a) angular separation and (b) maximum distance will the eye resolve them? Assume that the pupil diameter is 5.0mm, and use a wavelength of 550nm for the light. Also assume that diffraction effects alone limit the resolution so that Rayleigh’s criterion can be applied.

In Fig. 36-48, let a beam of x-rays of wavelength 0.125 nm be incident on an NaCl crystal at angle θ = 45.0° to the top face of the crystal and a family of reflecting planes. Let the reflecting planes have separation d = 0.252 nm. The crystal is turned through angle ϕ around an axis perpendicular to the plane of the page until these reflecting planes give diffraction maxima. What are the (a) smaller and (b) larger value of ϕ if the crystal is turned clockwise and the (c) smaller and (d) larger value of ϕ if it is turned counter-clockwise

For three experiments, Fig. 36-31 gives αversus angle θ in one-slit diffraction using light of wavelength 500 nm. Rank the experiments according to (a) the slit widths and (b) the total number of diffraction minima in the pattern, greatest first.

The telescopes on some commercial surveillance satellites can resolve objects on the ground as small as across (see Google Earth), and the telescopes on military surveillance satellites reportedly can resolve objects as small as 10cm across. Assume first that object resolution is determined entirely by Rayleigh’s criterion and is not degraded by turbulence in the atmosphere. Also assume that the satellites are at a typical altitude of 400nmand that the wavelength of visible light is role="math" localid="1663028559183" 550nm. What would be the required diameter of the telescope aperture for (a) role="math" localid="1663028596951" 85cmresolution and (b) role="math" localid="1663028635287" 10cmresolution? (c) Now, considering that turbulence is certain to degrade resolution and that the aperture diameter of the Hubble Space Telescope is role="math" localid="1663028673584" 2.4m, what can you say about the answer to (b) and about how the military surveillance resolutions are accomplished?

A source containing a mixture of hydrogen and deuterium atoms emits red light at two wavelengths whose mean is 656.3 nm and whose separation is 0.180 nm. Find the minimum number of lines needed in a diffraction grating that can resolve these lines in the first order.

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free