1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Real and apparent depth

  1. Mar 7, 2015 #1
    1. The problem statement, all variables and given/known data
    Hi. I need help with homework. the correct answers have been provided in the question. one doesn't match with mine and the other does. I don't understand how the one answer can be correct when its dependent on my incorrect answer.

    A transparent cube of 15cm edge contains a small air bubble. its apparent depth when viewed when viewed from one face of the cube is 6cm and when viewed from the opposite face is 4cm. what is the refractive index of the substance of the cube and what is the actual distance of the bubble from the first face.
    Answers: Refractive index=1.5 real depth=9cm

    2. Relevant equations
    apparent depth/real depth=n2/n1

    3. The attempt at a solution
    6/real depth=n2/1
    6=n2*real depth
    rd=6/n2...(1) where rd=real depth


    substitute (1) into (2)
    n2=refractive index=2/3 (I thought the lowest refractive index was that in a vacuum where its 1)

    6/real depth=2/3/1
    6=2/3*real depth
    real depth=9cm
  2. jcsd
  3. Mar 7, 2015 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Hello SammyD97. Welcome to PF ! (I thought I should be first to reply considering our user names.)

    Your second answer is correct, because you make the same mistake in arriving at both answers, but the effect is to compensate for the mistake made in getting the first one.

    Check on what you have done as follows:
    Use the correct index of refraction, 1.5, and use your method to predict the apparent distance, knowing that the true distance is 9 cm from a surface.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Real and apparent depth
  1. Apparent Depth? (Replies: 1)

  2. Apparent depth (Replies: 2)