physics
posted by emi .
A CONVEX LENS PRODUCES O REAL AND INVERTED
IMAGE 2.5 TIMES MAGNIFIED AT A DISTANCE OF 25CM FROM THE LENS.CALCULATE THE FOCAL LENGTH OF THE LENS,

physics 
Elena
2.5x/25 = x/do
do=25x/2.5x=10cm
1/di+1/do=1/f
1/25 + 1/10 =1/f
7/50=1/f
f=50/7=7.14 cm
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