Energy of incident of light to amplitude of light?

  1. 1. The problem statement, all variables and given/known data
    A sheet of glass transmit 70% of the energy of the incident light
    What is the value of the quantity: (Amplitude of transmitted light) / (Amplitude of incident light)

    2. Relevant equations
    Intensity is proportional to amplitude square.

    3. The attempt at a solution
    I tried relating to the above equation but i got 0.7^2/1^2=0.49 (A) but answer is not A...
  2. jcsd
  3. Doc Al

    Staff: Mentor

    Why did you square the ratio of intensities?
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