Problem 2: (2 Mark) (a) In a diffractometer experiment a specimen of thorium (Th) is irradiated with tungsten radiation of λ= 1.476 x 10-¹0 m. Calculate the angle, 0, of the 4th reflection which is 311? Hint: Atomic volume of thorium is 19.9 cm³/mol. (1 Mark) (b) Suppose that the experiment described in part (a) is repeated but this time the incident beam consists of neutrons instead of x-rays. What must the neutron velocity be in order to produce reflections at the same angles as those produced by x-rays in part (a)? (1 Mark)