Electromagnetic Waves Quiz-2

EM waves can transport energy;

The (instantaneous) energy density (energy per unit volume) of the electric and magnetic fields, of an em wave, are equal, respectively, to

It has been experimentally demonstrated that

The total energy transferred to a (perfectly black) surface of area A (located normal to the direction of propagation of the EM wave) and thickness d, by an em wave, over one complete cycle, can be expressed as

The intensity (I) of an em wave (having $E_0$ and $B_0$ as the ‘peak values’ for its electric and magnetic fields), can be expressed in the form:

The peak value of the electric field, in the light radiated by a given (point) source of power P, at a point distance r, from the source equals.

An em wave, originating from a source, is radiating out 10 J of energy per second. At a distance of 50 cm from the source, a perfectly reflecting surface, of area $8\pi cm^2$, has these em waves incident on it. The average force, exerted on the surface, during a 30 seconds span would be

The rms value, of the electric field, in the em waves, produced a point source, at a distance of $\left(\frac{4}{\sqrt{\pi}}\right)$ in from the point source, is $2Vm^{-1}$. Taking $\varepsilon_0=8.85\times10^{-12}$ SI units and $C = 3 \times 108 \, ms ^{-1},$ we would find the power of the source to be (nearly)

The ratio, of the rms values of the magnetic fields in the em waves, radiated by two point sources, at points distance r and R, respectively, from the two sources, is ‘s’. If the power of one of the sources is P, that of the other would be

The peak value of the magnetic field, at a certain point, for an em wave is 9 nT. (It is given that $\mu_0=4\pi\times10^{-7}$ SI units and $c = 3\times10^8 ms^{-1}$). The peak value, of its electric field, and its intensity, at the same point, would be (nearly)