List of top Physics Questions on Electromagnetic Waves asked in CBSE CLASS XII

The ratio of amplitude of electric field to the amplitude of the magnetic field associated with an electromagnetic wave propagating in glass \((n=1.5)\) is :
Depict the variation of electric field (\(\vec{E}\)) and magnetic field (\(\vec{B}\)) with respect to the direction of propagation of an electromagnetic wave. Write their two important characteristics.
Show that \(\frac{1}{\sqrt{\mu_0 \varepsilon_0}}\) gives the velocity of an electromagnetic wave in free space.
A plane electromagnetic wave travels through a medium and the magnetic field associated with it is given by \[ B = 5 \times 10^{-8} \sin (3 \times 10^{10} t - 150 x) \text{ T} \] where \(x\) is in metres and \(t\) is in seconds. The velocity of the wave is :
An electromagnetic wave is propagating along x-axis. At any instant, the phase difference between the electric field ($\vec{E}$) and magnetic field ($\vec{B}$) is
An electromagnetic wave passes from vacuum into a dielectric medium with relative electrical permittivity \(\dfrac{3}{2}\) and relative magnetic permeability \(\dfrac{8}{3}\). Then, its
The magnetic field in a plane electromagnetic wave travelling in glass \((n = 1.5)\) is given by \[ B_y=(2\times10^{-7}\,\text{T})\sin(\alpha x+1.5\times10^{11}t) \] where \(x\) is in metres and \(t\) is in seconds. The value of \(\alpha\) is:
An electromagnetic wave is propagating along x-axis. At any instant, the phase difference between the electric field ($\vec{E}$) and magnetic field ($\vec{B}$) is
An electromagnetic wave passes from vacuum into a dielectric medium with relative electrical permittivity \(\dfrac{3}{2}\) and relative magnetic permeability \(\dfrac{8}{3}\). Then, its
The magnetic field in a plane electromagnetic wave travelling in glass \((n = 1.5)\) is given by \[ B_y=(2\times10^{-7}\,\text{T})\sin(\alpha x+1.5\times10^{11}t) \] where \(x\) is in metres and \(t\) is in seconds. The value of \(\alpha\) is:
X-rays are more harmful to human beings than ultraviolet radiations because X-rays:
Estimate the ratio of shortest wavelength of radio waves to the longest wavelength of gamma waves.
An electromagnetic wave is travelling in vertically upward direction. At an instant, its electric field vector points in west direction. In which direction does the magnetic field vector point at that instant?
How is an electromagnetic wave produced?
(a) On what factors does the speed of an electromagnetic wave in a medium depend?
(b) How is an electromagnetic wave produced?
(c) Sketch a schematic diagram depicting the electric and magnetic fields for an electromagnetic wave propagating along the z-axis.
Write the drawbacks of Rutherford’s atomic model. How did Bohr remove them? Show that different orbits in Bohr’s atom are not equally spaced.
Name the parts of the electromagnetic spectrum which are absorbed by the ozone layer in the atmosphere.
(i) Name the parts of the electromagnetic spectrum which are also known as ‘heat waves’.
The electromagnetic waves used to purify water are:
The electric field in an electromagnetic wave in vacuum is given by:
\(\vec{E} = 6.3 \, N/C} \left[\cos \left(1.5 \, rad/m} \cdot y + 4.5 \times 10^8 \, rad/s} \cdot t\right)\right] \hat{i}\) % Part (a) Wavelength and Frequency Calculation (a) Find the wavelength and frequency of the wave:
Which one of the following has the highest frequency?
Electromagnetic waves with wavelength 10 nm are called:
(i) Derive the impedance of an R-C series circuit connected to an AC source v = v_m sin(ωt).
(ii) When does an inductor act as a conductor? Explain.
(iii) A lamp (R) and inductor (L) in series with 220V-50Hz AC give 11A. With 110V DC, it gives 11A. Find L.
Differentiate between diffusion and drift current. Explain their role in p-n junction formation.
Electric and magnetic fields of EM waves are: