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

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?
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.
(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.
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:
(i) Why do long-distance radio broadcasts use short-wave bands?
(ii) Why are optical and radio telescopes built on the ground, but X-ray astronomy is possible only from satellites orbiting the Earth?
In the four regions, I, II, III, and IV, the electric fields are described as: Region I: $E_x = E_0 \sin(kz - \omega t)$
Region II: $E_x = E_0$
Region III: $E_x = E_0 \sin kz$
Region IV: $E_x = E_0 \cos kz$
The displacement current will exist in the region:
Explain the following giving reasons:
(i) Electromagnetic waves differ considerably in their mode of interaction with matter.
(ii) Food items to be heated in microwave ovens must contain water.
(iii) Welders wear face mask with glasses during welding.
What is meant by displacement current? How is this current different from the conduction current? A capacitor is being charged by a source of emf. Justify the continuity of current in the circuit.
Name the electromagnetic waves with their wavelength range which are used for:
(i) FM radio broadcast
(ii) Detection of fracture in bones
(iii) Treatment of muscular strain
The phase difference between electric field \( \vec{E} \) and magnetic field \( \vec{B} \) in an electromagnetic wave propagating along the z-axis is: