The layer of the atmosphere that reflects low frequency $(LF)$ electromagnetic waves during day time only is

The electric field in an electromagnetic wave is given by $\overrightarrow{E} = \hat{i} 40 \cos \omega(t - \frac{z}{c}) \text{ N/C}$. The magnetic field induction of this wave is (in $SI$ units):

$A$ flood light is covered with a filter that transmits red light. The electric field of the emerging beam is represented by a sinusoidal plane wave
$E_x=36\,\sin\,(1.20 \times 10^7z -3.6 \times 10^{15}\,t)\,V/m$
The average intensity of the beam will be.....$W/m^2$

Light is an electromagnetic wave. Its speed in vacuum is given by the expression

$A$ magnetic field vector in an electromagnetic wave is represented by $\vec{B} = B_0 \sin(2\pi vt - \frac{2\pi x}{\lambda}) \hat{j}$. Its associated electric field vector is . . . . . . .

The biological importance of the ozone layer is that: