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Homework Help: Physics: Geometric Optics

  1. Sep 27, 2005 #1
    In my first two of weeks we covered most of the light unit, and i was sick(in class, but coulnd't focus or abosrb information) and now i am at the end of the unit with this due tomoro and i do not understand how to do any,

    I need to learn how to do this, I can't understand most of it right now, i need to learn so i can pass the unit test.

    Please help me

    3.Although red means "stop" and green means "go" red light actually travels faster then green light. What does this indicate about:
    A) the relative indices of refraction for red and green light in glass
    B) the angles of refraction for each colour, for the same angle of incidence

    4. A ray of light in air, with an incident angle of 40(degrees), has an angle of refraction of 20(degrees in "goop". If the light travels from "goop" to air, with an incident angle of 35(degree), determine th angle of refraction.

    5.After taking grade 11 physics, a student throws a loonie into a pool late one night in order to demonstrate refraction to his friends. the loonie sits on the bottom of the rool under 2.4 m of water and 2.0 m from the edge of the rool. the pyysics geek directs a flashlight beam over the edge of the pool to illuminate the coin. at what angle relative to the pool wall must the flashlight be aimed?

    6.A person's vision in one eye is corrected using a lens with a power of -2.0 d
    a) explain what vision defect is being corrected
    b)if a 10cm high object is located 75cm from the lens, determine the magnification of the immage.

    7. the eyepiece of a compound microscope has a focal length of 20mm, the objective has a focal length of 2mm. the lenses are fixed 175mm apart and the final image is formed 250mm from the eyepiece. determine the distance of the object from the objective lens

    8. light strikes a rectangular piece of crown glass with an angle of incidence of 30(degrees). If the block of glass is 10cm , determine the measure of lateral displacement.

    Please instruct me how to complete theese problems so i can have this done for tomoro
  2. jcsd
  3. Sep 27, 2005 #2
    Please someone read this, i have two hours before i am finished with this please help me!!!! I don't understand there is no way i can do this on my own, please, just give me some help,
  4. Sep 27, 2005 #3
    do you not have a text book im sure you could read some of it wich would probably help more than a verbal explanation? Are u familiar with trigonmetry? you will also need to know snells law llook it up in your text book. Diagrams will help to especially for questions like 5. When you ahve snells law it is basically jsut plug ur values in and solve it.
  5. Sep 27, 2005 #4
    n1sin(theta)1 = n2sine(theta)2
  6. Sep 27, 2005 #5
    I have a text book, but its on cd and extremely hard to navigate, and just reading from a text book doens't make sense, these problems are very badly worded,
  7. Sep 27, 2005 #6
    k ill walk u through 4 because im bored but jsut keep in mind i hvant done those problems since last year so im not promising nething

    n1sin(theta)1 = n2sin(theta)2

    the beam of light shines through the goop at an angle of 20 degrees so that is your first angle so it is the sin(theta) value. n1 is the index of refraction(in the goop) you want to find. now u want to look in your book or search google and u will get a vaule for the index of refraction of air i cant recall it from memory plug that in for n2. plug 35 in for your second angle

    n1(20) = (refraction for air)(20)
    solve that
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