How does refraction of light in water affect the perceived location of objects?

Click For Summary
SUMMARY

The discussion centers on the optical phenomenon of light refraction in water, specifically regarding how it affects the perceived location of objects submerged in water. A child standing at the edge of a 1.2m deep swimming pool sees a brick at a horizontal distance of 2.0m due to the refractive index of water, which is 1.33. The confusion arises from the distinction between the actual position of the brick, which corresponds to the refracted ray, and the perceived position, which aligns with the straight line extension of the light ray to the child's eye. This clarification is essential for accurately solving problems involving refraction.

PREREQUISITES
  • Understanding of Snell's Law and light refraction
  • Basic knowledge of geometry related to light paths
  • Familiarity with the concept of refractive index
  • Ability to interpret diagrams illustrating light behavior
NEXT STEPS
  • Study Snell's Law and its applications in optics
  • Learn how to calculate the actual position of submerged objects using refraction
  • Explore the concept of apparent depth and its implications in physics
  • Investigate practical applications of refraction in lenses and optical devices
USEFUL FOR

Students of physics, educators teaching optics, and anyone interested in understanding the principles of light behavior in different mediums.

CAF123
Gold Member
Messages
2,918
Reaction score
87
Hi,
I was trying the following question;
'A child of height 90 cm is standing at the edge of a 1.2m deep swimming pool. She
looks into the water and sees a brick lying on the bottom of the pool. From the
child's perspective, the brick appears to be 2.0m horizontally away from the side
of the pool. In reality, how far away is the brick from the side of the pool? (The
refractive index of water is 1.33. Assume the child's eye level is at 90 cm and the
pool is completely filled with water.)'

I know how to solve the problem, it is just I am having a little difficulty with some of the details. I took it to mean that the actual position of the brick would be the position that would be observed if there was no water, in which case it would be at the location following the straight ray (see diagram). I then took it to mean that the observed position would be at the position of the refracted ray . However, the solution has these the other way round - that is, the actual position at the refracted ray and observed position at the straight ray.( This is shown in the attachment)

Any clarification of why this is would be very helpful,
Thanks.
 

Attachments

  • Refraction.png
    Refraction.png
    6.5 KB · Views: 644
Physics news on Phys.org
We see an object in the direction from where the light ray emerging from the object arrives. A light ray from the brick (red) refracts somewhere at the surface of water and arrives at the eye of the child. The child observes the brick in the extension (blue) of the straight line hitting his eye.

ehild
 

Attachments

  • refraction.JPG
    refraction.JPG
    4.2 KB · Views: 621

Similar threads

Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
675
Replies
14
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
17K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 4 ·
Replies
4
Views
8K