The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagating in vacuum is equal to
$c$
$\frac{1}{c}$
$1$
None of these
Which scientist first time produced electromagnetic waves in laboratory?
A plane electromagnetic wave travels in vacuum along $z-$ direction. What can you say about the directions of its electric and magnetic field vectors? If the frequency of the wave is $30 \;MHz$, what is its wavelength in $m$?
The electric field associated with an em wave in vacuum is given by $\vec{E}=\hat{i} 40 \cos \left(k z-6 \times 10^{8} t\right)$ where $E, x$ and $t$ are in $volt/m,$ meter and seconds respectively. The value of wave vector $k$ is....$ m^{-1}$
The intensity of a light pulse travelling along a communication channel decreases exponentially with distance $x$ according to the relation $I = {I_0}{e^{ - \alpha x}}$ , where $I_0$ is the intensity at $x = 0$ and $\alpha $ is the attenuation constant. The attenuation in $dB/km$ for an optical fibre in which the intensity falls by $50$ percent over a distance of $50\ km$ is
A plane electromagnetic wave of wave intensity $6\, W/ m^2$ strikes a small mirror area $40 cm^2$, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be