The electric field associated with an e.m. wave in vacuum is given by vector E = i 40 cos (kz – 6 × 108 t), where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is
(a) 2 m–1
(b) 0.5 m–1
(c) 6 m–1
(d) 3 m–1
Correct option: (a) 2 m–1
Explanation:
