Doctor prescribes spectacles to a patient with a combination of a convex lens of focal length 40 em- and concave lens of focal length 25 em then the power of spectacles will be-6-5 D-8-5 D-1-5 D1-5 D

Question

Toppr Admin · Accepted Answer

For combination of lenses- powerP-P1-P2-10040-x2212-10025-x2212-1-5D

doctor prescribes spectacles to a patient with a combination of a convex lens of focal length 40 em, and concave lens of focal length 25 em then the power of spectacles will be.
-6.5 D
-8.5 D
-1.5 D
1.5 D

For combination of lenses, power
$P = P_{1} + P_{2} = \frac{100}{40} - \frac{100}{25} = - 1.5 D$

doctor prescribes spectacles to a patient with a combination of a convex lens of focal length 40 em, and concave lens of focal length 25 em then the power of spectacles will be.-6.5 D-8.5 D-1.5 D1.5 D

For combination of lenses, powerP=P1+P2=10040−10025=−1.5D

doctor prescribes spectacles to a patient with a combination of a convex lens of focal length 40 em, and concave lens of focal length 25 em then the power of spectacles will be.
-6.5 D
-8.5 D
-1.5 D
1.5 D

For combination of lenses, power
$P = P_{1} + P_{2} = \frac{100}{40} - \frac{100}{25} = - 1.5 D$