When an electron in an excited Mo atom fall from L to K shell; an X- ray is emitted. These X-rays are diffracted at angles of 7.75° by planes with a separation of

2.64Å. What is the difference in energy between K- shell an L – shell in Mo assuming a first-order diffraction (sin 7.75° = 0.1349)

a. 36.88 x 10^-19  j

b. 27.88 x 10 10^-16  j

c. 63. 88 x 10 10^-17  j

d. 64. 88 x 10  10^-16  j

Ans. b

(11)