Question

A double convex lens has two surfaces R1 =2cm,R2=5cm and refractive index n=3.find focal length​

Answer 1

Step-by-step explanation:

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Answer 2

Answer:

focal length=0.714cm

Step-by-step explanation:

1/f=(3-1)(1/2+1/5)

1/f=2×(5/10+2/10)

1/f=7/5

f=5/7=0.714cm

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1/f=(1/R1+1/R2)(n-1)