Ch 10Wave Optics — Class 12 Physics, concept-first.

WBCHSE's Unit 6, "Optics", is built in two sub-topics. SUB TOPIC 1 treats light within the ray (geometrical) picture -- reflection and refraction at plane and curved surfaces, lenses, mirrors, and the…

A wavefront is defined as the locus of all the points in a medium that are vibrating in the same phase at a given instant of time -- every point lying on one wavefront is, at that instant, at the iden…

Consider a plane wavefront travelling through a medium and about to strike a plane reflecting surface , making an angle of incidence with the normal to the surface at the point where it first touches…

The same construction, applied at a refracting interface separating two media of speeds (medium 1, where the wave is incident) and (medium 2, where it is transmitted), yields Snell's law.

When light waves from two (or more) sources overlap in a region of space, the resultant intensity at any point depends on the phase relationship between the waves arriving there, a phenomenon called i…

In Young's arrangement, a narrow slit illuminated by a monochromatic source sends out a single expanding wavefront, which is allowed to fall symmetrically on two further narrow slits and , cut very cl…

Let be a point on the screen at a distance from the central point , in a Young's double slit set-up with slit separation and screen distance .

The position of the th bright fringe above the central point is found by setting the path-difference condition for a maximum, , equal to the geometrical expression for path difference derived above:

When a plane monochromatic wavefront falls normally on a single narrow slit of width , Huygens' principle again applies -- but now every point across the width of the same slit acts as a source of sec…

Because light bends around edges (diffracts) at any finite aperture, the image of even a perfect point object formed by any real optical instrument is not a point but a small diffraction pattern -- a…

For an astronomical telescope, the same Rayleigh criterion is applied to the diffraction pattern formed at the circular aperture of the objective (lens or mirror), of diameter , rather than to a slit…

Light is a transverse electromagnetic wave, meaning the oscillating electric field associated with it always points in a direction perpendicular to the direction the wave is travelling in -- but in or…

Ordinary reflection also produces partial polarization, and at one particular angle of incidence, called the polarizing angle (or Brewster's angle) , the reflected ray becomes completely (100 percent)…

Huygens' principle -- every point on a wavefront is a source of secondary wavelets, and the new wavefront is their forward common tangent -- lets the laws of reflection () and refraction (, Snell's la…

Sample papers and previous-year board questions for this subject.