Homework Statement
A 5cm mirror is just large enough to show the whole image of a tree when held 20 cm from the eye of the observer whose distance to the tree is 100 m. What is the height of tree?
Homework Equations
n/a
The Attempt at a Solution
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Homework Statement
if the velocity of light in the medium is assumed to be 2.10^-8 m/s, how much time does it take the light to travel through the distance of 60 cm?
Homework Equations
n/a
The Attempt at a Solution
i tried to do something but not enough.. :(