--%>

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 : Explain Event horizon Event horizon:

    Event horizon: The radius which a spherical mass should be compressed to in order to convert it into a black hole, or the radius at which the time and space switch responsibilities. Once within the event horizon, it is basically impossible to escape t

  • Q : Define Cosmic background radiation or

    Cosmic background radiation: primal glow: The background of radiation is generally in the frequency range of 3 x 1011 to 3 x 108 Hz discovered in space in the year 1965. It is believed to be the cosmologically re

  • Q : Law of Machines Describe briefly all

    Describe briefly all the Law of Machines?

  • Q : Concept of nuclear reaction Describe in

    Describe in brief the concept of nuclear reaction?

  • Q : How asteroids are formed Explain how

    Explain how asteroids are formed? Describe.

  • Q : Define Static limit Static limit : The

    Static limit: The distance from a rotating black hole where no spectator can possibly stay at rest (with respect to the far-away stars) since of inertial frame dragging; this area is external of the event horizon, apart from at the poles where it meet

  • Q : Problem on synchronous TDM We require

    We require using synchronous TDM and joining 20 digital sources, each of 100 Kbps. Each and every output slot carries 1 bit for each digital source, however one extra bit is added up to each frame for synchronization.

    Q : Explain Daltons law of partial pressures

    Dalton's law of partial pressures (J. Dalton): The net pressure of a mixture of ideal gases is equivalent to the sum of the partial pressures of its components; which is the sum of the pressures which each component would exert when it were present al

  • Q : Define Sievert or SI unit of dose

    Sievert: Sv: The derived SI unit of dose equivalent, stated as the absorbed dose of the ionizing radiation multiplied by internationally-agreed-upon dimensionless weights, as various kinds of ionizing radiation cause various kinds of damage in the liv

  • Q : Define Watt or SI unit of power Watt: W

    Watt: W (after J. Watt, 1736-1819): The derived SI unit of power, stated as a power of 1 J acting over the period of 1 s; it therefore has the units of J/s.