X rays with a wavelength of 0.12 nm undergo first-order diffraction from a crystal at a 76 ? angle of incidence.

What is the angle of second-order diffraction?

m*? = 2d*sin(?)

where

? is the wavelength,

d is the distance between crystal planes,

? is the angle of the diffracted wave (Theta).

and m is an integer known as the order of the diffracted beam.

d=0.16nm/2*sin(69)

sin(Theta 2)=2*0.16nm/2*d

=2.14 degree

this is wrong someone help