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Physics Help!!

  • 28-02-2012 9:24am
    #1
    JackN688
    Closed Accounts Posts: 85 ✭✭


    I have an online assignment due and I have no idea
    Can someone help me


    1/What is the range of wavelengths that corresponds to green light for the human eye?
    577 – 492 nm
    455 – 390 nm
    492 – 455 nm
    780 – 620 nm
    620 – 597 nm
    597 – 577 nm

    2/Calculate the frequency (in [s-1]) for wavelength = 2.5m

    3/You stand at a diatance, d = 1.47 in front of a wall and gaze downward at a small vertical mirror mounted on it. In this mirror you can see the reflection of your shoes. If your eyes are at a height, h = 1.65 above your feet, through what angle should the mirror be tilted for you to see you eyes reflected in the mirror? (The location of the mirror remains the same, only its angle to the vertical is changed).where, h is the height of your eyes above your feet and d is the distance you stand from the mirror.


    Thank you :)


Comments

  • #2
    Kohl
    Closed Accounts Posts: 130 ✭✭Kohl


    JackN688 wrote: »
    I have an online assignment due and I have no idea
    Can someone help me


    1/What is the range of wavelengths that corresponds to green light for the human eye?
    577 – 492 nm
    455 – 390 nm
    492 – 455 nm
    780 – 620 nm
    620 – 597 nm
    597 – 577 nm

    2/Calculate the frequency (in [s-1]) for wavelength = 2.5m

    3/You stand at a diatance, d = 1.47 in front of a wall and gaze downward at a small vertical mirror mounted on it. In this mirror you can see the reflection of your shoes. If your eyes are at a height, h = 1.65 above your feet, through what angle should the mirror be tilted for you to see you eyes reflected in the mirror? (The location of the mirror remains the same, only its angle to the vertical is changed).where, h is the height of your eyes above your feet and d is the distance you stand from the mirror.


    Thank you :)

    The answer to the first one you can get on Wikipedia on the page Visible
    Spectrum. Read it because it explains which colours you can see and what wavelengths they are at.

    The answer to the second one uses the formula f = c/lambda, where c is the speed of light and the lambda is your wavelength.

    Thats a straightforward Pythagoras theorem in my opinion. You know two of the lengths of the triangle. Just work out the hypotenuse. You know that one angle in the triangle is 90 degrees, so you can use the sine rule to work out the angle.

    good luck.


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