There exists a uniform magnetic and electric field of magnitude $1\, T$ and $1\, V/m$ respectively along positive $y-$ axis. A charged particle of mass $1\,kg$ and of charge $1\, C$ is having velocity $1\, m/sec$ along $x-$ axis and is at origin at $t = 0.$ Then the co-ordinates of particle at time $\pi$ seconds will be :-
$(0,1,2)$
$(0, - {\pi ^2}/2, - 2)$
$(2, {\pi ^2}/2, 2)$
$(0, {\pi ^2}/2, 2)$
Show that average value of radiant flux density $'S'$ over a single period $'T'$ is given by $S = \frac{1}{{2c{\mu _0}}}E_0^2$.
The electric field of an electromagnetic wave in free space is given by $\vec E$$=10 cos (10^7t+kx)$$\hat j$ $volt/m $ where $t$ and $x$ are in seconds and metres respectively. It can be inferred that
$(1)$ the wavelength $\lambda$ is $188.4\, m.$
$(2)$ the wave number $k$ is $0.33\,\, rad/m.$
$(4)$ the wave is propagating along $+x$ direction.
Which one of the following pairs of statements is correct ?
A $1.5 \,kW$ laser beam of wavelength $6400 \,\mathring A$ is used to levitate a thin aluminium disc of same area as the cross-section of the beam. The laser light is reflected by the aluminium disc without any absorption. The mass of the foil is close to ......... $kg$
During the propagation of electromagnetic waves in a medium
A red $LED$ emits light at $0.1$ watt uniformly around it. The amplitude of the electric field of the light at a distance of $1\ m$ from the diode is....$ Vm^{-1}$