Electromagnetic Waves
CBSE Class 12 Physics · every board question from this chapter, 2022–2026
- A plane electromagnetic wave travels through a medium and the magnetic field associated with it is given by B=5 × 10^-8 sin (3 ×…2026
- An electromagnetic wave passes from vacuum into a dielectric medium with relative electrical permittivity (3/2) and relative…2026
- The magnetic field in a plane electromagnetic wave travelling in glass (n=1 · 5) is given by B_y=(2 × 10^-7 T) sin (α x+1 · 5 ×…2026
- The ratio of amplitude of electric field to the amplitude of the magnetic field associated with an electromagnetic wave…2026
- The expression of magnetic fields associated with four electromagnetic waves are given below: I. B_1=(4 × 10^-6 T) sin [0.7 ×…2026
- Electromagnetic waves used for purification of water are2026
- The electric field and the magnetic field components of an electromagnetic wave travelling in vacuum are represented as E=m sin…2026
- Electromagnetic waves used in a diagnostic tool in medicine have a wavelength range2026
- Welders wear special glass goggles or face masks with glass windows to protect their eyes from2026
- An electromagnetic wave is propagating along x-axis. At any instant, the phase difference (in radian) between the electric field…2026
- What is meant by displacement current? A capacitor is being charged by a battery. Show that Ampere-Maxwell law justifies…2026
- Name the electromagnetic waves which are used for (i) detection of fractures in bones (ii) physiotherapy (iii) radar systems Also…2026
- Name the electromagnetic waves which are used 3 (i) as a diagnostic tool in medicine (ii) in remote switches for TV sets (iii) in…2026
- What are infrared waves? Why are these waves referred to as 'heat waves'? Give any two uses of these waves.2026
- Depict the variation of electric field ( E) and magnetic field ( B) with respect to the direction of propagation of an…2026
- What is displacement current (i_d)? Considering the case of charging of a capacitor, show that i_d=ε_0 (d φ_E)/dt. What is the…2026
- What are microwaves? How are they produced? Give any two uses of microwaves.2026
- Differentiate between conduction current and displacement current. A capacitor is connected across a source providing…2026
- Name the electromagnetic waves which are (i) also known as 'heat waves', (ii) used in LASIK eye surgery, (iii) used to destroy…2026
- The given diagram exhibits the relationship between the wavelength of the electromagnetic waves and the energy of photon…2025
- The electric field in space between the plates of a parallel plate capacitor (each of area 2.5 × 10^-3 m^2 ) is changing at the…2025
- X-rays are more harmful to human beings than ultraviolet radiations because X-rays -2025
- Which one of the following correctly represents the change in wave characteristics (all in vacuum) from microwaves to X-rays in…2025
- Which of the following rays coming from the Sun plays an important role in maintaining the Earth's warmth?2025
- The amplitude of electric field in an electromagnetic wave in free space is 1000 Vm^-1. The amplitude of the magnetic field in…2025
- In an electromagnetic wave travelling in free space, the amplitude of magnetic field is 6.0 × 10^-4 T. The amplitude of its…2025
- The dimensions of (μ ε)^-1, where ε is permittivity and μ is permeability of a medium, are:2025
- Which of the following electromagnetic waves has photons of largest momentum?2025
- Assertion: EM waves do not require a medium for their propagation. Reason (R): EM waves are transverse waves.2025
- The electric field E of an electromagnetic wave propagating in north direction is oscillating in up and down direction. Describe…2025
- How is an electromagnetic wave produced? An electromagnetic wave is travelling in vertically upward direction. At an instant, its…2025
- How are electromagnetic waves produced? Write the wavelength range and one use of: (i) Microwaves, and (ii) Ultraviolet waves.2025
- Differentiate between 'conduction current' and 'displacement current', giving one similarity and one dissimilarity between them.…2025
- Name the electromagnetic wave used (i) in radar, (ii) in eye surgery and (iii) as diagnostic tool in medicine. Write their…2025
- State any three characteristics of electromagnetic waves. Briefly explain how and where the displacement current exists during…2025
- Name the electromagnetic radiations and write their frequency range: Used to take the photograph of the bones Produced by hot…2025
- The electromagnetic waves used to purify water are2024
- Welders wear special glass goggles or face masks with glass windows to protect their eyes from radiations produced by welding…2024
- Electromagnetic waves with wavelength 10 nm are called:2024
- In four regions I, II, III and IV, the magnetic field is given by: I. B_y=B_0 sin kz II. B_y=B_0 cos kz III. B_y=B_0 sin (kz-ω t)…2024
- Which one of the following has the highest frequency?2024
- Electromagnetic waves with frequency 1.0 × 10^18 Hz are known as:2024
- The first scientist who produced and observed electromagnetic waves of wavelengths in the range 25 mm-5 mm was:2024
- The electric and magnetic fields of electromagnetic waves are:2024
- A plane electromagnetic wave is travelling in air in +x direction. At a particular moment, its electric field E is along +y…2024
- In the four regions, I, II, III and IV, the electric fields are described as: Region I: E_x=E_0 sin (kz-ω t) Region II: E_x=E_0…2024
- The phase difference between electric field E and magnetic field B in an electromagnetic wave propagating along z -axis is -2024
- On what factors does the speed of an electromagnetic wave in a medium depend? How is an electromagnetic wave produced? Sketch a…2024
- The electric field in an electromagnetic wave in vacuum is given by: E=(6 · 3 N / C)[ cos (1 · 5 rad / m) y+(4 · 5 × 10^8 rad /…2024
- Name the part of the electromagnetic spectrum which are (i) stopped by face mask worn by welders. (ii) used in detectors in Earth…2024
- Name the parts of the electromagnetic spectrum which are (i) also known as 'heat waves' and (ii) absorbed by ozone layer in the…2024
- What is meant by displacement current? How is this current different from the conduction current? A capacitor is being charged by…2024
- "The wavelength of the electromagnetic wave is often correlated with the characteristic size of the system that radiates." Give…2024
- Name the electromagnetic waves with their wavelength range which are used for (i) FM radio broadcast (ii) detection of fracture…2024
- Explain the following giving reasons: (i) 'Electromagnetic waves differ considerably in their mode of interaction with matter'.…2024
- The ratio of the magnitudes of the electric field and magnetic field of a plane electromagnetic wave is2023
- An electromagnetic wave is produced by a charge2023
- The electromagnetic waves used in radar systems are:2023
- Which one of the following electromagnetic radiation has the least wavelength?2023
- Choose the correct option related to wavelengths ( λ ) of different parts of electromagnetic spectrum.2023
- E and B represent the electric and the magnetic field of an electro- magnetic wave respectively. The direction of propagation of…2023
- The electromagnetic radiations used to kill germs in water purifiers are called:2023
- Name the electromagnetic waves also known as 'heat waves'.2023
- Electromagnetic waves of wavelength of the order of a few meters were first produced and detected in the laboratory by:2023
- How are infrared waves produced? Why are these waves referred to as heat waves? Give any two uses of infrared waves. OR How are…2023
- What is meant by the term 'displacement current'? Briefly explain how this current is different from a conduction current.2023
- How are electromagnetic waves produced? Write their two characteristics.2023
- Identify the electromagnetic radiation and write its wavelength range, which is used to kill germs in water purifier. Name the…2023
- Identify the electromagnetic wave whose wavelengths range is from about 10^-12 m to about 10^-8 m. 10^-3 m to about 10^-1 m.…2023
- What is a displacement current? How is it different from a conduction current? OR Write any two characteristics of an…2023
- A plane electromagnetic wave propagates in vacuum along x -axis. Give the direction of electric field and magnetic field vectors.…2023
- Identify the part of electromagnetic spectrum which is: next to the lowest frequency end of the visible part of electromagnetic…2023
- (i) Depict a plane electromagnetic wave propagating along the x-axis. Write the expressions for its oscillating electric and…2022
- Identify electromagnetic waves which: (i) are used in radar system. (ii) affect a photographic plate. (iii) are used in surgery.…2022
- (i) Arrange the following electromagnetic radiation in the ascending order of their frequencies: X-rays, microwaves, gamma rays,…2022
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