Two waves A and B of frequencies 2MHz and 3 MHz, respectively are beamed in the same direction for communication via sky wave. Which one of these is likely to travel longer distance in the ionosphere before suffering total internal reflection?

Explanation

As the frequency of wave B is more than wave A, it means the refractive index of wave B is more than refractive index of wave A (as refractive index increases with frequency increases).
For higher frequency wave (i.e., higher refractive index) the angle of refraction is less i.e., bending is less. So, wave B travel longer distance in the ionosphere before suffering total internal reflection.