PYQ Vault
EbooksTutor

Power or focal length of the pieces of a cut lens

This type of question, asked 4 times: 27 Jun 2022, 13 Apr 2023, 22 Jan 2025, 29 Jan 2025. All 4 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    27 Jun 2022

    106
    A convex lens has power P. It is cut into two halves along its principal axis. Further one piece (out of the two halves) is cut into two halves perpendicular to the principal axis (as shown in figure). Choose the incorrect option for the reported pieces.

    Tap an option to check your answer.

  2. Question 2

    13 Apr 2023

    111
    A bi convex lens of focal length 10 cm10\text{ }cm is cut in two identical parts along a plane perpendicular to the principal axis. The power of each lens after cut is ____\_\_\_\_ D.

  3. Question 3

    22 Jan 2025

    76
    A symmetric thin biconvex lens is cut into four equal parts by two planes AB and CD as shown in figure. If the power of original lens is 4D then the power of a part of the divided lens is

    Tap an option to check your answer.

  4. Question 4

    29 Jan 2025

    82
    Two identical symmetric double convex lenses of focal length ff are cut into two equal parts L1, L2L_{1},{\text{ }L}_{2} by ABAB plane (containing the principal axis) and L3,L4L_{3},L_{4} by XYXY plane (perpendicular to the principal axis, through the centre) as shown in figure respectively. The ratio of focal lengths of lenses L1L_{1} and L3L_{3} is

    Tap an option to check your answer.