Statement-I : Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communication using sky wave propagation
Statement-II : The refractive index of the ionosphere becomes very high for frequency.

Statement-1 : Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communications using sky wave propagation. Statement-2: The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency.

Statement-1 : Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communications using sky wave propagation. Statement-2: The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency.

Statement-1 : Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communications using sky wave propagation. Statement-2: The refractive index of the ionosphere becomes very high for frequenceis higher than the criritcal frequency.

Electromagnetic waves with frequency greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation, because:

Electromagnetic waves with frequency greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation, because:

Assertion : Electromagnetic waves with frequencies more than the critical frequency of ionosphere cannot be used for communication using sky wave propagation. Reason : The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency .

Assertion : Electromagentic waves with frequencies more than the cirtical frequency of ionosphere cannot be used for communication using sky wave propagation. Reason : The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency .