We all know that the nucleus of Fe is most stable. So whenever a nuclear fission occurs, one of the daughter nuclei must be Fe in order to increase stability. Then why is it not so??

 A Converging bundle of light rays in the shape of cone with a vertex angle of 45° falls on a circular diaphragm of 20 cm diameter. A lens with power 5D is fixed in the diaphragm. Diameter of face of lens is equal ot that of diaphragm. If the vertex angle of new cone is 0, then tane =

(A) 1.5

(B) 2

(C) 3

(D) 1