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Homework Help: Geometrical optics, refraction

  1. Jun 23, 2016 #1
    1. The problem statement, all variables and given/known data
    A spherical surface of roc 10 cm separates 2 media x and y of refractive indices 3/2 and 4/3 respectively. Centre of the spherical surface lies in the denser medium. An object is placed i x medium. For image to be real, the object distance must be ----

    A) >90 cm

    B) <90 cm

    C) >80 cm

    D) <80 cm

    2. Relevant equations- i don't know relevant questions

    3. The attempt at a solution
    I used the formula u2/v - u1/u = (u2 - u1)/R. Where u2= 3/2 and u1= 4/3. But i dont think that that is right.
  2. jcsd
  3. Jun 23, 2016 #2
    The equation which you used
    Is correct
    Just set the boundary conditions
    And use proper sign convention
    (If the light ray is incident from the denser medium to the rarer, the image distance and radius are positive and the object distance is negative)
    Remember that the image formed is a real one and thus will converge at one point or the other in the denser or the rarer medium
    The distance of the image will be measured from the boundary obviously
    The formula
    Is used is
    That for
    Refraction at A Spherical Interface

  4. Jun 23, 2016 #3
    Object dist. Tending to infinite? And img dist. 'f'? That didn't gave me the answer. Please post the exact solution.
  5. Jun 24, 2016 #4
    Is the object placed in the first medium??
    (The rarer one?)
    I can give you small hints
    But I cannot give you the entire answer
  6. Jun 24, 2016 #5
    I got it. I placed object in the wrong medium. My bad
  7. Jun 24, 2016 #6
    I got it. I placed object in the wrong medium. My bad
  8. Jun 24, 2016 #7
    Glad you could realise it

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