f = + 10 cm m = v / u = 5 hence v = 5 u
Using the lens formula 1 / f = 1 / u + 1 / v => 1 /10 = 1 / u + 1 / 5 u (replacing v with 5 u) 1 / 10 = 6 / 5 u, hence 5 u = 60 giving u = 12 cm (the lens should be placed 12 cm from the illuminated object)
Mutiso answered the question on October 15, 2018 at 18:02
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