Question

If two lenses of power + 1.5 D and +1.0 D are placed in contact, then the effective power of combination will be :

• A. 4.5 D
• B. 2.5 D
• C. 5.4 D
• D. 4.2 D

Answer 1

The correct option is B 2.5 D

Given,

$P_1=+1.5D$

$P_2=+1.0D$

The effective power of the combination,

$P=P_1+P_2$

$P=(+1.5)+(+1.0)$

$P=+2.5D$

The correct option is B.