Answer:
15.32°
Explanation:
We have given the wavelength 
Diffraction grating is 1460 lines per cm
So
(as 1 m=100 cm )
For maximum diffraction
here m is order of diffraction
So 


The second one is correct not sure about the first one sorry
Denser materials tend to be closer to earths center due to their mass gravity is shown by the equation mg
Which stands for mass x gravity.