Diffraction Grating: 520nm & 630nm Wavelengths, 6000 Lines/cm, m=0-2 Fringes

[rojasharma]

light wavelengths of 520nm and 630nm passes through a diffraction grating that contains 6000lines/cm. a) sketch a diagram of the image produced from m=0 to m=2. label the order of each fringe.b) calculate the angles for the first and second-order maxima that would appear on the screen. c) What is the lowest value of m for which the 520-nm line no longer exists? I have no idea how to do this question:(..

 

[mysqlpress]

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/gratcal.html

 

[rojasharma]

i still don;t get it :(

 

[mysqlpress]

i still don;t get it :(

you have all the data u want...
For (1) , there is a central maximum at theta =0 where the two rays coincide...
and the greater the wavelength , the greater the theta the ray is for the same order...
(sin function is increasing between 0 to pi/2)
(2) sintheta = nlamda/d
you have the slit separation , lamda and n , so it is possible to calculate


c) No longer exist when sin theta >1

 

[rojasharma]

the picture will be similar to the one shown in the website?..do i need to use protractor for that?

 

[mysqlpress]

the picture will be similar to the one shown in the website?..do i need to use protractor for that?

sketch... I don't think you need to do that

 

[rojasharma]

label the order of each fringe? what does this mean?

 

[rojasharma]

for part b) sintheta=mlmbda/d...do i use both wavelengths? or a difference of the wavelengths?...confused:S