Question 169: Ray Optics

Question

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 figures). Choose the incorrect option for the reported pieces.

Accepted Answer

We know $$P = {1 \over f} = (\mu  - 1)\left( {{1 \over {{R_1}}} - {1 \over {{R_2}}}} \right)$$
$${L_1}:{1 \over {{f_1}}} = (\mu  - 1)\left( {{1 \over {{R_1}}} - {1 \over {{R_2}}}} \right) = {P_1} = (\mu  - 1)\left( {{2 \over R}} \right) = P$$
$${L_2}:{1 \over {{f_2}}} = (\mu  - 1)\left( {{1 \over {{R_1}}}} \right) = {P_2} = {{\mu  - 1} \over R}$$
$${L_3}:{1 \over {{f_3}}} = (\mu  - 1)\left( { - {1 \over {{R_2}}}} \right) = {P_3} = {{\mu  - 1} \over R}$$

Answer

Power of $${L_1} = {P \over 2}$$

Answer

Power of $${L_2} = {P \over 2}$$

Answer

Power of $${L_3} = {P \over 2}$$

Answer

Power of L1 = P

Ray Optics

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 figures). Choose the incorrect option for the reported pieces.

Choose the correct answer: