WAVE OPTICS

PRINCIPLE OF SUPERPOSITION When two or more waves simultaneously pass through a point, the disturbance of the point is given by the sum of the disturbances each wave would produce in absence of the other wave(s). In case of wave on string disturbance means displacement, in case of sound wave it means pressure change, in case of Electromagnetic Waves. it is electric field or magnetic field. Superposition of two light travelling in almost same direction results in modification in the distribution of intensity of light in the region of superposition. This phenomenon is called interference. Superposition of two sinusoidal waves: Consider superposition of two sinusoidal waves (having same frequency), at a particular point. Let, and, represent the displacement produced by each of the disturbances. Here we are assuming the dis- placements to be in the same direction. Now according to superposition principle, the resultant displacement will be given by, x, (t) a, sin ot x2(t)-a2 sin (ot + ) x(t) x,(t) X2(t) where A2 a12 + a22 + 2a, . a, cos and tang-a1+a2 cos a1 sin ot + a2 sin (ot+0) Asin (ot + %) a2 sino

s, and S, are two sources of light which produce individually disturbance at point P given by E, 3sin ot, E2 4 cos ot. Assuming E1 & E2 to be along the same line, find the resultant after their superposition. s,// E-E+ ,-5sin (ot + tan", 4/3) E 3 sinot4 sin(ot ) 2 A3+4+2(3) 4) cos -5 2 4 sin 2 4 tano 530 3 +4cos 2

SUPERPOSITION OF PROGRESSIVE WAVES; PATH DIFFERENCE: Let S, and S2be two sources producing progressive waves (disturbance travelling in space given by , and y) At point P y, a, sin (ot-kx, + y.-a, sin (ot-kx, + .) 2 Here, the phase difference, Here p is the path difference Clearly, phase difference due to path difference k (path difference) 2T where k-

For Constructive Interference: n -0, 1, 2 or max 2 Intensity, /ImaxV12- For Destructive interference: (2n + 1 )T, x = (2n + 1)A/2 or, Intensity,-/1 min 11-V12

Light from two sources, each of same frequency and travelling in same direction, but with intensity in the ratio 4 1 interfere. Find ratio of maximum to minimum intensity. 2 1 2 2+1 2-1 max V2

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Kartikey Pandey

IIT BHU(B.Tech)| Super 30 Physics Faculty | FOUNDER of New era online coaching.
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Bilas Kumar

10 months ago

nice sir g

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JR

Jinnies Rego

9 months ago

sir please follow b m Sharma while teaching and please upload those vdos which are not uploaded by new era that way u r completing the entire syllabus

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Hardik Dwivedi dwivedi

9 months ago

sir ji please aap please mangnetism ke videos bhi daaal dijiye .

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Lithesh Shetty

9 months ago

@kpsir sir upload all 12 th videos first next month u can upload 11 physics plz sir

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Lithesh Shetty

9 months ago

@kpsir sir upload all 12 th videos first next month u can upload 11 physics plz sir

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RK

Rishabh Kumar

9 months ago

sir, waves ka nhi lecture daliye

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