NAGALAND Class 12-science Physics Ray Optics and Optical Instruments
Reflection by Spherical Mirrors1. A convex mirror has a wider field of view as compared to a concave mirror
2. All distances are measured from the pole of the mirror along the principal axis. Distances measured in the same direction as the incident light are positive.
3. Distances measured in the direction opposite to incident light are negative. m = image height / object height.
When m is positive, image is erect and when m is negative, the image is inverted.
Refraction by Plane SurfacesLaws of refraction, definition of refractive index. Some phenomenon due to refraction through place surfaces.
Total Internal ReflectionTotal internal reflection occurs when light strikes a denser medium at an angle larger than the critical angle.
Critical angle is the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90 degree.
Important applications of total internal reflection include optical fibers and totally reflecting prisms.
Refraction by Spherical SurfacesStudy of refraction at spherical surfaces. Understand various sign conventions for spherical surfaces. Derive single Refracting surface equation. Learn to draw ray diagrams for image formation by thin lenses.
Refraction by Lens1. Lens makerandrsquo;s formula 1/f = (n2-n1)/n1(1/R1-1/R2
2. Thin lens formula 1/v - 1/u = 1/f
3. Power = 1/focal length.
4. Power for a converging lens is positive and for a diverging lens is negative.
5. The effective focal length of combination of lens of focal length f1,f2,f3andhellip;andhellip;is f, where 1/f = 1/ f1 +1/f2 +1/f3 +.......
6. If m1,m2,m3...
Refraction and Dispersion by PrismRefraction through a prism. Dependence of deviation on incident angle. Formation of spectrum.
Natural Phenomena Due to SunlightNatural phenomena due to Sunlight
Optical InstrumentsConstruct and learn the working principle of a Compound microscope and an Astronomical telescope. State and compare magnifying powers of these optical instruments.