Answer:
A.2.95 m
B.7
Explanation:
We are given that
Diffraction grating=600 lines/mm
d=
Wavelength of light,
l=4.6 m
A.We have to find the distance between the two m=1 bright fringes

For first bright fringe, =1


The distance between two m=1 fringes

Hence, the distance between two m=1 fringes=2.95 m
B.For maximum number of fringes,


Substitute the values


Maximum number of bright fringes on the scree=
-the contact force
-weight of an object
-the surfaces in contact (coefficient of friction).
these are what I think are the answer