Question

1. A spectroscopic lamp has been displayed for you to determine the spectroscopic wavelengths in this lab practical. Using the three most prominent spectroscopic lines, fill in the table below from the longest wavelength to the shortest. 3SigFigs no units required.

wavelength (nm)

2. Using the table provided, identify the gas by the two character abbreviation. _____________

Ne (nm)	Hg (nm)	He (nm)	Cl (nm)	Kr (nm)
540	440	490	440.0	445
610	545	590	490.0	560
620	577/579	660	650.0	590
640
650

3. N is the rating of a diffraction grating in lines/centimeter.

Calculate d, the distance between adjacent lines, in micrometers.

N	d
8.0000E+28.0000E+2 lines/cm	____________ μm

In the figure directly below the quantities A, y, and d are spectrometer parameters which are given in the Spectrometer Parameters below the diagram, The diffraction spots are indicated by the solid dots. Use the equation for constructive interference, d sin(θ)=mλ, enter your answer for the wavelength:

Spectrometer Parameters

d	2.4000E+02.4000E+0micrometers
A	7.4000E+17.4000E+1mm
y	1.0000E+11.0000E+1mm

4. The calculated wavelength is_______nm to 4SigFigs.

Answer 1

1) There is supposed to be a spectrum along with this question.

As I have seen this question earlier, I can answer this part.

The most prominent wavelengths in the spectrum are at

• 445 nm
• 555 nm and
• 585 nm

2) To get the name of the gas used in the lamp, we have to compare the prominent wavelengths from the lamp in part 1 and the table given.

From the table, we can see that the wavelengths are closest to mercury.

3) The number of lines per centimetre of the grating is

N = 8*10^2

So, distance between two lines is

d = 1/(8*10^2) = 0.00125 cm = 12.5*10^-6 m = 12.5

4) It is given that

For a grating spectrometer,

Taking m = 1

Using the values from the question