List of top Physics Questions on Electromagnetic waves

The correct increasing order of wavelength for UV, Visible light, and Microwaves is:
A thin charged spherical shell of radius \(10\,cm\) has a uniform surface charge density of \(20\,pC/cm^{2}\). The electric potential at a point \(8\,cm\) from the centre of the shell is:
Two large, thin, parallel sheets have surface charge densities of opposite signs and equal magnitude \(\sigma\). What is the magnitude of the electric field \((E)\) in the region between the sheets?
Three charges \(+20\,\mu C\), \(+20\,\mu C\) and \(-20\,\mu C\) are placed at the vertices \(A\), \(B\) and \(C\) respectively of an equilateral triangle of side \(1\,m\). Find the net force acting on the charge at vertex \(A\).
A \(1\,\mu F\) capacitor is charged to \(12\,V\) and then connected to an identical uncharged capacitor. What will be the common potential?
A sphere encloses charges \(+5\,C\) and \(-2\,C\), while a charge \(-3\,C\) is outside the sphere. What is the electric flux through the sphere?
An electromagnetic wave has a frequency of 150 MHz. Its wavelength in air is approximately:
The CORRECT statement among the following regarding electromagnetic waves is
The amplitude of the magnetic field of a plane electromagnetic wave travelling along positive x-axis in vacuum is 6 mT. A particle of charge 5 \(\mu\)C is travelling with a velocity of \(6\times10^{5}ms^{-1}\) along the positive y-axis. If the magnetic field is oriented along positive z-axis, then the maximum force exerted on the particle due to electric field of the wave is
The rms value of electric field at a distance of 6 m from a 100 W bulb of efficiency 1.2% is:
The rms electric field of an EM wave is $30\sqrt{\pi}\ \text{V m}^{-1}$. Find its intensity in free space.}
The average force exerted on $5 cm^2$ area of a non-reflecting plate in 10 minutes when light with an energy flux of $20\,W\,cm^{-2}$ incidents normally on it is}
If a plane electromagnetic wave of intensity $9 \times 10^5\text{ W}\cdot\text{m}^{-2}$ incidents normally on a perfectly absorbing surface of area $2\text{ m}^2$ for a time of $180\text{ s}$, then the average force exerted by the electromagnetic wave on the surface during this time is:
The unification of electromagnetism and optics is based on the discovery that
If the average energy density of the electric field of an electromagnetic wave is $U_E$ and the average energy density of the magnetic field of the wave is $U_B$, then:
In an electromagnetic wave in vacuum, the relation between peak electric field E_0 and magnetic field B_0 is:
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) :} The electromagnetic wave exerts pressure on the surface on which they are allowed to fall.
Reason (R) :} There is no mass associated with the electromagnetic waves.
In the light of the above statements, choose the correct answer from the options given below :
A magnetic field vector in an electromagnetic wave is represented by
$\vec{B} = B_0 \sin \left( 2\pi \nu t - \frac{2\pi x}{\lambda} \right) \hat{j}$. Its associated electric field vector is _______.
An electromagnetic wave travels in free space along the x-direction. At a particular point in space and time, \( B = 2 \times 10^{-7} \hat{j} \) T is associated with this wave. The value of the corresponding electric field \( E \) at this point is _______ V/m.}
The electric field of an electromagnetic wave travelling through a medium is given by \[ \vec{E}(x,t)=25\sin(2\times10^{15}t-10^{7}x)\,\hat{n}. \] Then the refractive index of the medium is ________. (All given measurements are in SI units)
For an electromagnetic wave propagating through vacuum, \( \vec{k},\vec{E}\) and \( \omega \) represent propagation vector, electric field and angular frequency respectively. The magnetic field associated with this wave is represented by :
The electric field associated with an electromagnetic wave travelling in vacuum is given by \[ \vec E = E_0\sin(3y+4z+\omega t)\,\hat i \] where \(\omega\) is the angular frequency. All quantities are in SI units. The correct statement(s) about this wave is/are: \[ [\text{Given: speed of light in vacuum }c=3\times10^8\ \text{m s}^{-1}] \]
The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:
What range of electromagnetic spectrum is considered as light?
Match the following Maxwell's equations: (The symbols used here have their usual meanings)