Tough concepts made easy
5 min read

Ray Optics And Optical Instruments

- Are you feeling tough? Let make it extremely simple
Angle of Deviation in prism and the factors affecting it:
The variation in angle of deviation in a prism depends on several factors like:
  • angle of incidence i
  • material of the prism, i.e. its R.I.
  • angle of prism A
  • colour (wavelength) of incident light
Factors Affecting Angle of Deviation
8 mins
Lens Maker's Formula Derivation:
The Lens Maker's Formula is directly a consequence of combining the results for two successive refractions at two spherical surfaces. The image formed by the first refracting surface becomes the virtual object for the second refracting surface. But its derivation is somewhat difficult due to so many variables. This video will simplify the derivation by accurately showing the simple geometrical parameters used.
Lens maker formula (short derivation) | Class 12 (India) | Physics | Khan Academy
15 mins
Compound Microscope as an improvisation of Simple Microscope:
They say Two Heads is Better than One. A simple microscope uses one convex lens and has a limited maximum magnification ( 9) for realistic focal lengths. But for much larger magnifications, we use two lenses, one compounding the effect of the other. This video explains the working of a compound microscope.
5 mins
Combination of lenses:
If two or more thin lenses placed in contact are involved in the question then we can replace the lenses by the equivalent lens. The power of the equivalent lens can be found using the formula. If the power is known then it is trivial to calculate the focal length of the equivalent lens.
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Thin lenses in contact | Class 12 (India) | Physics | Khan Academy
8 mins
Sign convention rules
Sign convention rules are very confusing. We need to be very clear about the convention we are using and we should stick to the standard convention only.
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Here we will follow the simplified sign convention which creates no ambiguity.
1. Pole of the mirror or lens is considered as the origin. Right side of the pole is considered as the positive side and the left side is the negative side.
2. Upper side of the pole is considered as the positive side and the lower side is the negative side.
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Mirror Formula Sign Convention
9 mins