Light with a wavelength of 546.1 nm passes through a 6.62 103 lines cm diffraction grating. what is the first-order angle of
diffraction?
a 21.2°
c3920
b. 34.60
d 41.6

The first order angle of diffraction is 21.2°.

Option A

Explanation:

It is known that light waves get diffracted through grating will undergo interference fringes. If the wavelength of light is comparable to the diameter of grating then constructive interference will be formed if and only if the diffracted line obey Bragg’s law i.e.,

Here d is the grating constant.

Here N is the number of lines per cm.

Hence,

Thus, we get,

Then the diffraction angle θ can be found as below with n=1 as we need to determine the first order diffraction angle.                    

Thus, obtaining the first- order diffraction angle as,

he . if i may ask what i your question exactly?

explanation:

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west