RAY OPTICS AND OPTICAL INSTRUMENTS in 40 Minutes || Complete Chapter For JEE Main/Advanced

JEE Wallah32 minutes read

Himanshu Gupta introduces children to Physics Valhalla for a session on Ray Optics, covering topics like reflection, refraction, and optical instruments for exams. The lecture delves into concepts like the Law of Reflection, velocity of images, spherical mirrors, lens formulas, refraction, and dispersive power to enhance understanding of optics.

Insights

  • The session on Ray Optics and Optical Instruments by Himanshu Gupta covers crucial topics such as reflection, refraction, spherical mirrors, lens formulas, and refractive index, emphasizing the significance of these concepts for exams and practical understanding.
  • Various laws and formulas are discussed, including the Law of Reflection, the refractive index calculation, lens and mirror formulas, and the principles governing optical instruments, providing a comprehensive overview of how light behaves in different mediums and the mechanics behind image formation in optical systems.

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Recent questions

  • What topics are covered in Physics Valhalla's session on Ray Optics and Optical Instruments?

    Various topics such as reflection, refraction, spherical mirrors, and optical instruments.

  • What is the Law of Reflection discussed in the Physics Valhalla session?

    The Law of Reflection states that the angle of incidence equals the angle of reflection.

  • How is the refractive index calculated in the Physics Valhalla session?

    The refractive index is calculated as the speed of light in vacuum divided by the speed of light in the medium.

  • What is the formula for refraction from a spherical surface discussed in the session?

    The formula for refraction from a spherical surface is μ1/u + μ2/v = -μ1/r.

  • What are some examples of optical instruments covered in the Physics Valhalla session?

    Optical instruments discussed include the simple microscope, compound microscope, terrestrial telescope, and astronomical telescope.

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Summary

00:00

Physics Valhalla: Ray Optics Essentials for Kids

  • Himanshu Gupta welcomes children to Physics Valhalla for a session on Ray Optics and Optical Instruments using Mind Maps.
  • The lecture aims to cover important concepts quickly, noting the chapter's significance for exams.
  • Topics to be covered include reflection by plane mirror, reflection from spherical mirror, and refraction.
  • The session will also discuss refraction from a lens, refraction from a prism, and optical instruments.
  • Reflection involves the Law of Reflection where the angle of incidence equals the angle of reflection.
  • The number of images formed between two mirrors at an angle is determined by dividing 360 by the angle.
  • The velocity of the image in relation to the object and mirror movement is discussed.
  • The field of vision determines where an object's image is visible.
  • The rotation of incident and reflected rays is explained based on mirror and image movement.
  • Spherical mirrors are discussed, including the mirror formula, sign conventions, magnification, and ray diagram rules.

13:49

Understanding Refractive Index and Lens Formulas

  • Refractive index is the ratio of the speed of light in vacuum to the speed of light in a medium.
  • The refractive index is always greater than or equal to one.
  • The refractive index is calculated as the speed of light in vacuum divided by the speed of light in the medium.
  • Frequency of light remains constant when changing mediums.
  • Refraction occurs when light passes through transparent materials, causing lateral displacement.
  • The formula for refraction from a spherical surface is μ1/u + μ2/v = -μ1/r.
  • Magnification is calculated as V/μ2, where μ2 is the refractive index of the medium.
  • The lens formula is 1/V - 1/U = 1/F, or -1/U + 1/V = 1/F.
  • The power of a lens is μ2/V1, and it depends on the surrounding medium.
  • When combining lenses, the power of convex lenses is considered positive, while diverging lenses are negative.

27:54

"Optical Division, Refractive Index, and Instruments"

  • Minimum division occurs when the angle of incidence and angle of emergency are equal, resulting in R1 and r2 being equal to A/2.
  • The refractive index in the condition of minimum division is calculated using the formula μ = sin(delmin + A/2) / sin(A/2).
  • A thin prism with an angle less than 7 degrees is called a thin press, and in such cases, the division for near normal incidence of light is given by μ - 1 * A.
  • The dispersive power, which indicates the amount of dispersion created per unit deflection, is calculated as μ * A.
  • The refractive index for yellow light is determined by the formula A + B / λ, where A and B are constants.
  • Optical instruments include the simple microscope, compound microscope, terrestrial telescope, and astronomical telescope, each serving to magnify images for the retina based on angular magnification.
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