Which of the following statement is false for the properties of electromagnetic waves ?
These waves do not require any material medium for propagation
Both electric and magnetic field vectors attain the maxima and minima at the same place and same time
The energy in electromagnetic wave is divided equally between electric and magnetic field vectors
Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of wave
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
If an electromagnetic wave propagating through vacuum is described by $E_y=E_0 \sin (k x-\omega t)$; $B_z=B_0 \sin (k x-\omega t)$, then
A lamp emits monochromatic green light uniformly in all directions. The lamp is $3\%$ efficient in converting electrical power to electromagnetic waves and consumes $100\,W$ of power . The amplitude of the electric field associated with the electromagnetic radiation at a distance of $5\,m$ from the lamp will be nearly.......$V/m$
Suppose that intensity of a laser is $\left(\frac{315}{\pi}\right)\, W / m ^{2} .$ The $rms$ electric field, in units of $V / m$ associated with this source is close to the nearest integer is $\left(\epsilon_{0}=8.86 \times 10^{-12} C ^{2} Nm ^{-2} ; c =3 \times 10^{8} ms ^{-1}\right)$
Write characteristics of electromagnetic waves.