$A$ microwave and an ultrasonic sound wave have the same wavelength. Their frequencies are in the ratio (approximately):

This question has Statement $-1$ and Statement $-2.$ Of the four choices given after the Statements,choose the one that best describes the two Statements.
Statement $-1:$ Short wave transmission is achieved due to the total internal reflection of the $e-m$ wave from an appropriate height in the ionosphere.
Statement $-2:$ Refractive index of the ionosphere is independent of the frequency of $e-m$ waves.

Match the following List-$I$ with the List-$II$:

List-$I$	List-$II$
$(A)$ Gauss's law	$(I)$ Surface charge density
$(B)$ Faraday's law	$(II)$ Electric charge and energy conservation
$(C)$ Ampere's law	$(III)$ Change in magnetic flux
$(D)$ Kirchhoff's law	$(IV)$ Change in electric flux
	$(V)$ Total electric flux

Due to the tilting of the Earth,which waves finally disappear?

The graph between radiation power $P$ from a linear antenna and the square of the length of the antenna $l^2$ is shown in the figure for two antennas $A$ and $B$. If all other parameters are the same,find the ratio of the wavelengths of $A$ and $B$,i.e.,$\frac{\lambda_A}{\lambda_B}$.

Generation,propagation,and detection of electromagnetic waves is the basis of: