Exercise 1 - Calibrating the Diffraction Grating Click on the link below to view the diffraction pattern of a mercury lamp which emits a bluish color. The lamp will be used to calibrate the grating, i.e., to find the distance between adjacent slits, d and thus the number of lines per cm (1/d where d is in cm). Mercury emits three bright lines, a bluish-green line at 546 nm and two yellow lines at 577 nm and 579 nm. The two yellow lines are very close to each other and for the purpose of this exercise, they are treated as one line at 578 nm. Choose the wavelength according to the color line you measure

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do exactly like they told you. Take the answer you just got above and conver to cm and than take the inverse.

Example

d=1.27e^-6 m * 100 cm= 1.27e^-4cm

now take the inverse of d in cm...

(1.27e^-4)^-1=7874 no units for this answer

Example

d=1.27e^-6 m * 100 cm= 1.27e^-4cm

now take the inverse of d in cm...

(1.27e^-4)^-1=7874 no units for this answer

## Exerscise 2

same thing as the 1st part of number except you are now solving for the wavelength....

we just found d in part one so we will be using that number again... d=1.27e^-6m

in exercise two we are now looking for the wavelength...

so....

d * sin(theta)=wavelength

we just found d in part one so we will be using that number again... d=1.27e^-6m

in exercise two we are now looking for the wavelength...

so....

d * sin(theta)=wavelength

- d=d from exerscise 1
- theta you have to measure again and is specific to each line, make sure you measure the angle accurately or else you won't get the right answer.

## EXERCISE 3

For the last part match your wavelengths from part 2 to the ones in the chart link that closely matches yours