--%>

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 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 : Explain BCS theory BCS theory -  The

    BCS theory - The theory put forth to elucidate both superconductivity and super fluidity. This suggests that in the superconducting (or super fluid) state electrons form Cooper pairs, where two electrons proceed as a single unit. This takes a non

  • Q : Polar Materials The molecules of many

    The molecules of many dielectrics possess an electric dipole moment without having an external electric field. In such molecules centres of their positive and negative charges are displaced with respect to each other and therefore form a dipole. Such materials are kno

  • Q : What are Woodward-Hoffmann rules

    Woodward-Hoffmann rules: The rules leading the formation of products throughout certain kinds of organic reactions.

  • Q : Explain Cosmological constant

    Cosmological constant (Lambda): The constant mentioned to the Einstein field equation, proposed to admit the static cosmological solutions. At the time the present philosophical view was steady-state model of the space, where the Universe has been aro

  • Q : What is Kirchhoffs law of radiation

    Kirchhoff's law of radiation (G.R. Kirchhoff): The emissivity of a body is equivalent to its absorbptance at similar temperature.

  • Q : Difference between the cathode ray and

    Illustrate the difference between the cathode ray and beta ray?

  • Q : Define Pseudoforce Pseudoforce : The

    Pseudoforce: The "force" that arises as an observer is plainly treating an accelerating frame as an inertial one.

  • Q : Define anti-aliasing What do you

    What do you understand by the term anti-aliasing? Describe briefly?

  • Q : Define Charles law Charles' law (J.A.C.

    Charles' law (J.A.C. Charles; c. 1787): The volume of an ideal gas at constant (steady) pressure is proportional to the thermodynamic temperature of that gas.