Dispersion of light :- Dispersion of light is the phenomenon of splitting of a beam of white light into its 7 constituent colours when passed through a transparent medium like water droplets or Prism . It was discovered by Isaac Newton in 1666 . Newton discovered that light is made up of seven different colours…
Dispersion by a prism :- When white light ( Sun light ) is incident on a glass prism, the emergent light is seen to be consisting of several colours, the phenomenon of splitting of light into several component colours is known as dispersion. The different component colours that appear in sequence are violet, indigo, blue,…
Angle of deviation ( δ ) :- The passes of light through a triangular prism ABC, The angles of incidence and refraction at the first face AB are i₁ and r₁ while the angle of incidence at the second face AC is r₂ and the angle of refraction or emergence i₂ . The angle between…
Equivalent focal length of two lenses :- Let us consider two lenses L₁ ( focal length f₁ ) and L₂ ( focal length f₂ ) are separated by a distance d and P₂ is equivalent lens of both lenses ( focal length f ). Angle of deviation produce by the lenses P, L₁ and L₂…
Let us consider two lenses A anb B of focal length f₁ and f₂ placed in contact with each other. Let the object be placed at a point O beyond the focus of the first lens A. The first lens produces an image at I₁ is real, it serves as a virtual object for the…
Refraction of light at a convex surface :- 1. For real image :- The figure shows the geometry of formation of image I of an object O on the principal axis of a spherical surface ( convex ) with centre of curvature C and radius of curvature R. The rays are incident from a medium…
Twinkling of stars :- it is is a phenomenon of atmospheric refraction. Stars do not really twinkle they just appear to twinkle when seen from the surface of the earth. The star twinkling in the night because of the effect of our atmosphere. when starling enters our atmosphere it is affected by winds in the…
Total internal reflection :- when light travels from and optically denser medium to rarer medium at the interface, it is partly reflected back into the same medium and partly refracted to the second medium, this reflection is called the internal reflection. Conditions for the total internal reflection :- Critical angle ( Ic ) :- The…
Refraction of light :- when a beam of light encounters another transparent medium, a part of light gets reflected back into first medium while the rest enters the other, The direction of propagation of incident ray of light that enters the other medium changes at the interface of the two media. This phenomenon is called…
The mirror equation :- The ray diagram shows the image A’B’ of an object AB formed by a concave mirror . We derive the mirror equation or the relation between the object distance (u), image distance (v) and the focal length (f). From the above figure the two right angle triangle A’B’F and MPF are…
Consider a ray parallel to the principal axis strinking the mirror at M, CM will be perpendicular to the mirror at M. Let θ be the angle of incidence and MQ be the perpendicular from M on the principal axis, then ∠MCP = θ and ∠MFP =2θ Now tanθ =MQ/CQ and tan2θ = MQ/FQ for…
Definitions regarding spherical mirrors. Pole :- The geometric centre of a spherical mirror is called its pole. Denoted by ‘P’ Principal axis :- The line joining the pole and centre of curvature of the spherical mirror is known as the principal axis. Centre of curvature :- the point in the centre of the sphere from…
