The lattice spacing of the principal Bragg planes in sodium ...

[wenmo]

The lattice spacing of the principal Bragg planes in sodium chloride is 0.282 nm. For what wavelength of x-rays will the first order reflected beam diffract at 55 with respect to the normal to the crystal planes?
 
  A) 0.323 nm
  B) 0.530 nm
  C) 0.662 nm
  D) 0.150 nm
  E) 0.462 nm

Question 2

Reza's face is 20 cm in front of a concave shaving mirror having a focal length of magnitude 30 cm. How large is the image of his face?
 
  A) half as large as his face
  B) four times as large as his face
  C) three times as large as his face
  D) of the same size as his face
  E) twice as large as his face

[katkat_flores]

Answer to Question 1

A

Answer to Question 2

C

[wenmo]

Thanks for the timely response, appreciate it

[bassamabas]

Wow, this really help