'A single crystal of table salt (NaCl) is irradiated with beam of X-rays of unknown wavelength: The first Bragg reflection is observed at an angle of 26.3 degree
a) Given that the spacing between the interatomic planes in the NaCl crystal to be 0.282 nm what the wavelength of the X-ray?
b) What is the energy of the X-ray in eV?'