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Grade 12General Physics

A plano convex lens placed in air has curved surface aving radius of radius of curvature 60cm and it is made of refractive index 1.5.When the convex surface is silvered, the system will work as a concave mirror of focal length?

Profile image of Manish Balani
14 Years agoGrade 12
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1 Answer

Profile image of Shyama P
ApprovedApproved Tutor Answer14 Years ago

(1/f)=(1/fmirror)+(2/flens)

1/fmirror=2/R

1/flens=(1.5-1)/R   lens makers formula

         =1/2R

Sub.

1/f=3/R => f=20cm