Light, Mirrors, Lenses, immediate help required!

mhl2188

Hello, here is the problem i am having trouble with. The sun falls on a concave mirror and forms an image 3 cm from the mirror. If an object 24mm high is placed 12 cm from the mirror, where will its image be formed? So far, i have decided that since 1/f = 1/do + 1/di...
1/f = 1/do + 1/3 = 1/12 + 1/di
I also decided that hi/2.4 = -di/12... The problem is...even if i solve for di in terms of hi and plug that into my first equation i dont have enough information to solve for do. Im stuck and this problem is due tomorrow... please help
thanks
mhl

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OlderDan

Homework Helper
mhl2188 said:
Hello, here is the problem i am having trouble with. The sun falls on a concave mirror and forms an image 3 cm from the mirror. If an object 24mm high is placed 12 cm from the mirror, where will its image be formed? So far, i have decided that since 1/f = 1/do + 1/di...
1/f = 1/do + 1/3 = 1/12 + 1/di
I also decided that hi/2.4 = -di/12... The problem is...even if i solve for di in terms of hi and plug that into my first equation i dont have enough information to solve for do. Im stuck and this problem is due tomorrow... please help
thanks
mhl
You need to use the "sun" information to find the focal length of the mirror. The sun is an object at distance ___________ that forms an image at 3cm. What is f?

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