2. INDEX
S.No Topic Page
1 Aim
2 Apparatus Required
3 Theory
4 Procedure
5 Observation
6 Calculations
7 Results
8 Precautions
9 Sources of Error
10 Bibliography
3.
4. Procedure :-
1. Set the He-Ne laser source horizontally.
2. Place the diffraction grating between He-Ne laser source and screen.
3. Find out the principal maximum, 1st and 2nd order maximum.
4. Now measure the distance between diffraction grating and screen that
is D(cm).
5. measure the distance from principal maximum to 1st maximum that is
d(n=1).
6. Now find out the value of sinθ, by formula.
7. Repeat the steps 1-6 times for different distance D and note down that
reading.
5. OBSERVATIONS:-
1. Number of lines on the diffraction grating, N = 600 lines/mm
grating element, (e+d)= 1/N = 0.016 cm-1
S.No Order Distance between screen
And diffraction D(cm)
Distance of
maximum form
central point O(cm)
Sinθn = dn /√D2 + dn
2
1. 1 100 41 0.379
2. Number of lines on the diffraction grating, N = 300 lines/mm
grating element, (e+d)= 1/N = 10/300 = 0.033cm-1
S.No Order Distance between screen
And diffraction D(cm)
Distance of
maximum form
central point O(cm)
Sinθn = dn /√D2 + dn
2
1. 1 100 19.5 0.191
2. 1 100 19.8 0.194
6. S.N
o
Order Distance between screen
And diffraction D(cm)
Distance of
maximum form
central point O(cm)
Sinθn = dn /√D2 + dn
2
1. 1 100 6.5 0.0648
2. 1 100 6.7 0.0668
3. 1 100 6.8 0.0678
2. Number of lines on the diffraction grating, N = 300 lines/mm
grating element, (e+d)= 1/N = 10/300 = 0.033cm-1
