Question

an optician placed two convex lens of power +2D and +0.25D infront of a persons eye during eye testing. he immediately thinks that instead of these two a single lense can be used. find the power of single convex lens​

Answer 1

$\underline{\underline{\Large{\bf Given:-}}}$

$\bull\sf P_1=+2D$

$\bull\sf P_2=+0.25D$

$\underline{\underline{\Large{\bf To\:Find:-}}}$

$\bull\sf Equivalent\:power=P$

$\underline{\underline{\Large{\bf Solution:-}}}$

We know that

$\boxed{\sf P=P_1+P_2}$

$\\ \sf\longmapsto P=2D+0.25D$

$\\ \sf\longmapsto P=(2+0.25)D$

$\\ \sf\longmapsto P=2.25D$

$\underline{\therefore{\sf Power\:of\:the\:single\:convex\:lens\:is\:2.25D.}}$