(c) 1.38 eV (O O.oU E(x, y, z, t) = (3i + 4j) exp [i(ot kz)] represents an electromagnetic wave. Possible directions of the fast axis of a quarter wave plate converts this wave into a circular wave are (a)7i+jj and-i+] (b) 3-4j] and4-3j] 2 (o)1-4)j and14i+31 2 C7i-]and +7 V2