The monoenergetic beam of electrons moving along $+ y$ direction enters a region of uniform electric and magnetic fields. If the beam goes straight undeflected, then fields $B$ and $E$ are directed respectively along

An electromagnetic wave of frequency $1\times10^{14}\, hertz$ is propagating along $z-$ axis. The amplitude of electric field is $4\, V/m$ . lf ${\varepsilon_0}=\, 8.8\times10^{-12}\, C^2/Nm^2$ , then average energy density of electric field will be:

Assume a bulb of efficiency $2.5\%$ as a point source. The peak values of electric field produced by the radiation coming from a $100\, W$ bulb at a distance of $3\, m$ is respectively…..$V\,{m^{ – 1}}$

The electric field intensity produced by the radiation coming from a $100\, W$ bulb at a distance of $3\, m$ is $E$. The electric field intensity produced by the radiation coming from $60\, W$ at the same distance is $\sqrt{\frac{x}{5}} E$. Where the value of $x=……… .$

A radiation is emitted by $1000\, W$ bulb and it generates an electric field and magnetic field at $P$, placed at a distance of $2\, m$. The efficiency of the bulb is $1.25 \%$. The value of peak electric field at $P$ is $x \times 10^{-1} \,V / m$. Value of $x$ is. (Rounded-off to the nearest integer)

[Take $\varepsilon_{0}=8.85 \times 10^{-12} C ^{2} N ^{-1} m ^{-2}, c =3 \times 10^{8}$ $ms ^{-1}$ ]