--%>

calculate the intensity I along y axis

As shown in the figure below, a source at S is sending out a spherical wave:

E1=(A×D/r) cos(wt-2πr/λ); where r is the distance to source S. In addition, there is another plane wave propagating along x axis: E2=Acos(wt-2πx/λ). 

These two waves both projected on a vertical screen as shown in the figure. Please calculate the intensity I along y axis (I should be a function of y, the distance from x axis). D is the distance between the screen and the source.

 

381_optics.png

Hint: For a wave E=E0cos (wt + q), I = 2 = E02. Also r = (D2 + y2)1/2.

For k<<1,  (1+k2)1/2» 1+k2/2.   cosA+cosB = 2cos[(A+B)/2] cos[(A-B)/2]

   Related Questions in Physics

  • Q : Define Singularity Singularity : The

    Singularity: The center of a black hole, where the curvature of space-time is maximal. At singularity, the gravitational tides deviate; no solid object can yet theoretically survive beating the singularity. Though singularities usually predict inconsi

  • Q : Define Henry or SI unit of inductance

    Henry: H (after W. Henry, 1775-1836): The derived SI unit of inductance, stated as the inductance of a closed circuit in which the electromotive force of 1 V is generated whenever the electric current differs uniformly at a rate of 1

  • Q : What do you understand by the term

    What do you understand by the term Ambient Reflection? And also write down its characteristic?

  • Q : Define Photovoltaics Photovoltaics (PV)

    Photovoltaics (PV): It transform light directly into electricity. The typical current residential installation of 12m2 could produce around 1,300 kWh pa with a peak of around 1.9kW, though larger and more efficient installations are possibl

  • Q : Define Olbers paradox Olbers' paradox

    Olbers' paradox (H. Olbers; 1826): If the Universe is infinite, consistent, and unchanging then the whole sky at night would be bright -- concerning as bright as the Sun. The further you stared out into space, the more stars there would be, and theref

  • Q : Weak equivalence or principle of

    Weak equivalence principle: principle of uniqueness of freefall: The idea in general relativity is that the world-line of a freefalling body is sovereign of its composition, structure, or state. This principle, hold by Newtonian mechanics and gravitat

  • Q : Define Schwarzschild radius

    Schwarzschild radius: The radius ‘r’ of the event horizon for a Schwarzschild black hole of mass m is specified by (in geometrized units) r = 2 m. In its conventional units: r = 2 G m/c2

  • Q : Explain Chronology protection conjecture

    Chronology protection conjecture (S.W. Hawking): The notion that the formation of any closed time like curve will (automatically) involuntarily be destroyed by the quantum fluctuations as soon as it is made. In another words, the quan

  • Q : Describe Wien displacement law Wien

    Wien displacement law: For a blackbody, the product result of the wavelength corresponding to the maximum radiances and the thermodynamic temperature is constant, then the Wien displacement law constant. As an outcome, as the temperature increases, th

  • Q : Define Zeeman Effect or Zeeman line

    Zeeman Effect: Zeeman line splitting (P. Zeeman; 1896): Zeeman Effect is the splitting of lines in a spectrum whenever the source is exposed to the magnetic field.