A plano convex lens has a thickness of 4 ck. When placed on a horizontal table with the curved surface in contact withit, the apparent depth of the bottom most point of the lens is found to be 3 cm. If the lens inverted such that the plane face is in contact with the table, the apparent depth of the center of plane face is found to be 25/8 cm. Find the focal length of lens. Assume the thickness to be negligible while finding its focal length.

A plano convex lens has a thickness of 4 ck. When placed on a horizont

1.	A plano convex lens has a thickness of 4 ck. When placed on a horizontal table with the curved surface in contact withit, the apparent depth of the bottom most point of the lens is found to be 3 cm. If the lens inverted such that the plane face is in contact with the table, the apparent depth of the center of plane face is found to be 25/8 cm. Find the focal length of lens. Assume the thickness to be negligible while finding its focal length.
Answer» 75 cm 60 cm 20 cm 100 cm Answer :C

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