Hi there,
I need some help on a few questions pleaaase :)
4. An unknown lens has a focal length of +540mm, and is plano-convex in form. The radii are measured to be infinity and -305.95mm respectively.
What is the refractive index?
5. If an object is placed 50mm in front of a lens and the image is found to be 160mm behind the lens, what power is the lens?
6. A projection sight-testing chart is set to produce an image at a distance of 6m. If the lens in the projector has a power of +10.00D, how far from the len would the slide have to be placed? (Light shining through the transparent slide acts as a source).
7. Where is the image positioned when light from a small source passes through a lens with a focal length of +285.71mm which is positioned 120mm away?
8. Calculate the magnification and type of image produced when an object is placed 145mm in front of a lens of -7.25D
9. An inverted image half the size of an object is required. If the object must be placed 120mm from the lens, what is the power of the lens, and where would the image form?
10. Calculate the power of the lens required to produce an upright virtual image which is 0.8x the size of the object, if the object distance is to be 100mm.
11. What is the size and position of the image produced when an object 36mm high is places 25mm outside the focal length of a +8.00D lens?
NB: These are all assignment questions. I would love it if someone could give me a nudge in the right direction. I'm not here to cheat, I just don't have anyone to bounce ideas off over this side of the world :)
Thanks to all :cheers:
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