A ground receiver in line-of-sight communication cannot receive direct waves due to

• its low frequency

• curvature of earth

• its high intensity

• smaller antenna

72.

In an amplitude modulation with modulation index 0.5, the ratio of the amplitude of the carrier wave to that of the side band in the modulated wave is

• 4 : 1

• 1 : 1

• 1 : 2

• 2 : 1