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21.68 If you have a convex lens with 20cin focal length, where are the two lens

ID: 2098670 • Letter: 2

Question

21.68

If you have a convex lens with 20cin focal length, where are the two lens locations that will project an image of the light bulb onto the screen? Express your answers using two significant figures separated by a comma. at What's the magnification in the first case (smaller distance from the light bulb)? Express your answer using two significant figures. What's the magnification in the second case (larger distance from the light bulb)? Express your answer using two significant figures.

Explanation / Answer

suppose the distance of the lens from the bulb be x. so, distance of lens from screen = 1.02-x 1/v -1/u =1/f => 1/(1.02-x) -1/(-x) = 1/20 => x= 0.51, 0.51 d1 = d2= 0.51 cm m= v/u = (1.02-0.51)/(-0.51) = -1