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Homework Help: Laser Beam Wave Questions

  1. Nov 5, 2009 #1
    1. The problem statement, all variables and given/known data

    An argon laser emits 1 watt of continuous light (λ= 5.145 x 10-7 m) in a parallel beam of 2 mm diameter in vacuum.

    2. Relevant equations

    (a) What is the wavelength, frequency, period, wave number, velocity, intensity, and amplitude of the electric field of the laser light?

    b) What is the energy, the linear and angular momenta carried by each photon? What is the photon flux (the number of photons per time) of the laser light?

    (c) Assume that the laser beam is incident normally (θi = 0°) on the flat surface of a body. What pressure is exerted on the body when it fully absorbs the laser light? If the body fully reflects the laser light back, what is the pressure exerted on the body?

    (d) The laser beam is incident normally (θi = 0°) on the flat surface of a transparent glass block of refractive index n=1.5, and only the 96% of the incident power enters into the block. Which of the above quantities in (a) and (b) change for the transmitted light inside the glass block and what are the new values for the changed quantities.

    3. The attempt at a solution

    I really don't know where to start. Need help/hints for any parts. Thanks in advance!
  2. jcsd
  3. Nov 5, 2009 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Welcome to Physics Forums.

    You must know some equations that have to do with wavelength, frequency, period, and some of the other things being asked here :smile:
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