--%>

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 Heat pumps Heat pumps move heat

    Heat pumps move heat from one place to another. They work similar to refrigeration. The movement of heat takes energy, either electrical energy as in the use of  vapor compression heat pumps or thermal energy as in the use of absorption heat pump

  • Q : Define Le Chateliers principle Le

    Le Chatelier's principle (H. Le Chatelier; 1888): When a system is in equilibrium, then any modification imposed on the system tends to shift the equilibrium state to decrease the consequence of that applied change.

  • Q : Explain Lagrange points Lagrange points

    Lagrange points: The points in the vicinity of two massive bodies (like the Earth and Moon) with each others' relevant gravities balance. There are five, labeled L1 via L5. L1, L2, and L3 lie all along the centerline among the centers

  • Q : Scanning electron and transmission

    Give one benefit of a scanning electron microscope over the transmission electron microscope? Briefly explain it.

  • 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 : Explain Boyle's law Boyle's law (R.

    Boyle's law (R. Boyle; 1662); Mariotte's law (E. Mariotte; 1676) - The product result of the volume and pressure of an ideal gas at constant (steady) temperature is constant.

  • Q : Water drain contradict problem Does

    Does water drain contradict clockwise in the northern hemisphere and clockwise in the southern hemi-sphere? Briefly explain it.

  • Q : Define Second or SI unit of time

    Second: s: The basic SI unit of time, stated as the period of time equivalent to the duration of 9 192 631 770 periods of the radiation analogous to the transition between the two hyperfine levels of the ground state of cesium-133 atom.

  • Q : Explain Hawking radiation Hawking

    Hawking radiation (S.W. Hawking; 1973): The theory which black holes emit radiation similar to any other hot body. The virtual particle-antiparticle pairs are continuously being made in supposedly empty space. Infrequently, a pair wil

  • Q : Define Ideal gas constant or universal

    Define Ideal gas constant or universal molar gas constant? Ideal gas constant: or universal molar gas constant; R: The constant which appears in the ideal gas equation. It is equivalent to