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Real height and apparent height

  • Thread starter jadelamlam
  • Start date
1. The problem statement, all variables and given/known data

if the line of sight,object,image are collinear,we can apply the equation
d/D = n(medium containing observer) / n(medium containing object)
Where d = distance between image and boundary(apparent height/depth)
D = distance between object and boundary.(real height/depth)

If the line of sight is not perpendicular to the boundary of the media,the image I is along the line of sight.However the object O is not on the same line.
The equation d/D = n(medium containing observer) / n(medium containing object) is no longer correct.

In this situation,how can we find the exact position of I by algebraic method?

2. Relevant equations
d/D = n(medium containing observer) / n(medium containing object)

3. The attempt at a solution
please see the attachment,the words in blue is done by myself.

PS.the angle between line of sight and the horizontal = 180 - 90 - 33.7 = 56.3 degree
I don't think the real height = 4.38tan56.3 = 6.57m,as it is not necessary that I is perpendicular to Q(the object).

I think we have to know the horizontal and vertical distance between I and B in order to get the answer,is there any idea?

thx a lot


Hi jadelamlam!! :smile:

The position 'I' appears on the line of sight the camera has, because that's where it 'thinks' the light is coming from. Also, since it can only 'just' see the top flag, where would 'I' be on the line AB? :wink:
This is what I am asking for =.=,I don't know how to calculate the exact position of I.
Roughly estimate,I should be higher than Q and further away from B(I should lie on line AB)
Last edited:

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