An electromagnetic wave of frequency $\nu = 3.0\,MHz$ passes from vacuum into a dielectric medium with permitivity $\varepsilon = 4.0$. Then
Wavelength is doubled and the frequency remains unchanged
Wavelength is doubled and frequency becomes half
Wavelength is halved and frequency remains unchanged
Wavelength and frequency both remain unchanged
Light is an electromagnetic wave. Its speed in vacuum is given by the expression
Which of the following is not transported by electromagnetic waves?
The magnetic field in a plane electromagnetic wave is given by
${B_y} = \left( {2 \times {{10}^{ - 7}}} \right)\sin \left( {0.5 \times {{10}^3}x + 1.5 \times {{10}^{11}}t} \right)T$
$(a)$ What is the wavelength and frequency of the wave?
$(b)$ Write an expression for the electric field.
Sun light falls normally on a surface of area $36\,cm ^{2}$ and exerts an average force of $7.2 \times 10^{-9}\,N$ within a time period of $20$ minutes. Considering a case of complete absorption, the energy flux of incident light is.
The electric field associated with an $e.m.$ wave in vacuum is given by $\vec E = \hat i\,40\,\cos \,\left( {kz - 6 \times {{10}^8}\,t} \right)$. where $E$, $z$ and $t$ are in $volt/m$, meter and seconds respectively. The value of wave factor $k$ is ....... $m^{-1}$.