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Class 12 Physics Electromagnetic Waves in ONESHOT with PYQ Chapter 8 CBSE 2023-24 Party series🔥

Zaki Saudagar Physics・45 minutes read

The video highlights Physics preparation tips, including the importance of headphones for clarity, covering topics like EM Waves and Maxwell's experiments, while also introducing a platform for live classes with premium notes and a special deal for joining. It explains the concept of displacement current, Maxwell's equations, electromagnetic wave characteristics, and categorization based on frequency and wavelength, highlighting unique applications of specific waves like X-rays, gamma rays, and infrared waves.

Insights

  • Maxwell's experiments highlighted the concept of displacement current, showcasing how changing electric fields generate this new type of current, which was crucial in completing Ampere's circuit law.
  • Electromagnetic waves, characterized by perpendicular electric and magnetic fields, travel without a medium, follow principles like reflection and refraction, and are categorized based on frequency and wavelength, with ionizing waves on the right side of the spectrum used in medical applications, and non-ionizing waves on the left side utilized for communication purposes.

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Recent questions

  • What is displacement current?

    A: Displacement current is a concept introduced by Maxwell to correct Ampere's Circuital Law, accounting for changing electric fields. It is generated in regions where electric flux changes over time, leading to the discovery of a new type of current.

  • How are Maxwell's equations derived?

    A: Maxwell's equations compress electrostatics, electrodynamics, and magnetism into four equations. The first equation explains Gauss Law of Electrostatics, detailing flux due to charges within a closed surface. The second addresses Gauss Law in magnetism, where monopoles do not exist. Faraday's equation explains induced EMF, while Ampere's Modified Law combines conduction and displacement currents.

  • What are the characteristics of electromagnetic waves?

    A: Electromagnetic waves are produced by accelerated or oscillating charges, travel without a medium, and have a velocity equal to the speed of light. The electric and magnetic fields in these waves are always perpendicular, indicating their transverse nature and polarization. They follow principles like superposition, reflection, refraction, interference, diffraction, and polarization, enabling various phenomena to occur.

  • How are electromagnetic waves categorized?

    A: Electromagnetic waves are categorized based on frequency and wavelength, with visible light occupying a small portion in the middle of the spectrum. Ionizing forms are on the right side, used in medical and research fields, while non-ionizing forms are on the left, utilized for communication purposes like radar and cellphones.

  • What are the unique applications of X-rays and gamma rays?

    A: X-rays are used in cancer treatment, while gamma rays are employed in studying molecules. Remembering the frequency and wavelength of each wave is crucial for understanding their specific applications.

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Summary

00:00

Physics Exam Prep: EM Waves, Maxwell's Contributions

  • The video focuses on Physics preparation, emphasizing the importance of using headphones for better understanding.
  • The content covers the EM Wave chapter in detail, aiming to provide comprehensive exam preparation.
  • A new sample paper by Oswal Gurukul is recommended for Physics practice, available at a low price.
  • Premium notes for download are accessible through the video description.
  • The creator has launched a platform for live classes, offering detailed Physics courses with live sessions, recordings, notes, and test series.
  • A special deal is available for joining the live Physics course, covering NCRT questions and examples.
  • The NCRT line-by-line series is free on the channel, with a practice cover-up starting on December 14th.
  • Maxwell's experiments on changing magnetic fields leading to electric fields are explained, highlighting the concept of displacement current.
  • Maxwell's contribution in completing Ampere's circuit law is discussed, introducing the idea of two types of current: conduction and displacement.
  • The changing electric field between parallel plate capacitors results in a displacement current, showcasing the relationship between electric and magnetic fields.

11:55

Maxwell's Equations: Unifying Electricity and Magnetism

  • Displacement current is generated by changing electric fields, leading to the discovery of a new type of current.
  • Ampere's Circuital Law was incomplete as it only accounted for conduction current within wires.
  • Correcting the equation required considering both conduction and displacement currents as total current.
  • Maxwell's experiment proved Ampere's mistake and introduced displacement current.
  • Displacement current is produced in regions where electric and electric flux change over time.
  • Maxwell's equations compress electrostatics, electrodynamics, and magnetism into four equations.
  • The first equation explains Gauss Law of Electrostatics, detailing flux due to charges within a closed surface.
  • The second equation addresses Gauss Law in magnetism, where monopoles do not exist, resulting in a zero value.
  • Faraday's equation, the third equation, explains induced EMF depending on flux changes over time.
  • The fourth equation, Ampere's Modified Law, combines conduction and displacement currents to correct the original equation.

24:11

Understanding Electromagnetic Waves: Properties and Principles

  • Electromagnetic waves are seen traveling in the positive axis, with electric field in the y axis and magnetic field in the z axis.
  • The cross product concept explains that an electric field in one axis can have a magnetic field in the perpendicular axis, with the wave propagating in the remaining axis.
  • The equation of an electromagnetic wave involves the electric and magnetic fields, with the wave direction determined by the fields' orientations.
  • Electromagnetic waves encompass a spectrum, with visible light being a small portion of this spectrum.
  • The wave equation for an electromagnetic wave is derived from the standard wave equation, with the choice of plus or minus sign indicating the wave's direction.
  • The relation between the electric and magnetic fields in an electromagnetic wave is defined by a specific formula involving the velocity of light.
  • The velocity of an electromagnetic wave in a medium is determined by the medium's properties, with the refractive index indicating how light changes when moving between mediums.
  • Characteristics of electromagnetic waves include their production by accelerated or oscillating charges, their ability to travel without a medium, and their velocity being equal to the speed of light.
  • The electric and magnetic fields in an electromagnetic wave are always perpendicular to each other, indicating the wave's transverse nature and polarization.
  • Electromagnetic waves follow principles like superposition, reflection, refraction, interference, diffraction, and polarization, enabling various phenomena to occur.

36:06

Understanding Electromagnetic Waves and Their Applications

  • EM waves are categorized based on frequency and wavelength, with visible light occupying a small portion in the middle of the spectrum.
  • Ionizing forms of EM waves are found on the right side of the spectrum, primarily used in medical and research fields, while non-ionizing forms are on the left side, utilized for communication purposes like radar and cellphones.
  • Specific EM waves like X-rays and gamma rays have distinct uses, such as cancer treatment and studying molecules, with each wave's frequency and wavelength being crucial to remember.
  • Infrared waves are produced by hot bodies and are commonly used in remotes, with their frequency and wavelength being essential to memorize.
  • Ultraviolet radiation, X-rays, and gamma rays each have unique applications, such as killing germs in water, detecting cracks in railway tracks, and manufacturing polythene, respectively. Remembering their frequency and wavelength is vital for understanding their uses.
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