Question by Joel: how can i use mirrors and lenses to magnify the sun on a wall?
I am trying to aid physics teachers develop an activity that magnifies and projects an image of the sun so they can see sunspots employing only mirrors and lenses.

Best answer:

Answer by JullyWum
The link beneath describes a straight-forward method ..

Making use of window blinds (darkened room) would enhance the contrast of the Sun’s image .. naturally a suitable sized hole in the blind is essential to permit sunlight to enter !

Using person converging (convex) lenses ..
Preferably mount the lens with the shorter focal length to obtain sunlight .. find the focus point utilizing a piece of white paper to locate the smallest sun-spot behind the lens (the paper may possibly get burnt /catch alight)
Arrange the 2nd (extended focal length) convex lens so that the sun-spot image of the first lens is a few cms additional from this lens than it’s focal length .. so the 2nd lens can type an inverted and magnified true image of the sun-spot on a screen really a distance behind the 2nd lens.

Trail and error will be necessary in putting the 2nd lens to get a final focused image (but don’t let the sun-spot get closer than the focal length of the 2nd lens .. that would make a virtual image which can’t kind on a screen)

In no way appear directly at the Sun through these lenses .. see the warning in the link.

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how can i use mirrors and lenses to magnify the sun on a wall?
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