(a) Calculate the wavelength associated with a neutron moving at 2.60 km s⁻¹. Is this wavelength suitable for diffraction studies (m_n = 1.675 × 10⁻²⁷ kg)? 

(b) For magnetic neutron diffraction studies long neutron wavelengths are often needed; calculate the velocity of a neutron that has an associated wavelength of 5 Å.