A) 9D
B) 2D
C) 3D
D) 7D
Correct Answer: A
Solution :
We have the effective power given by \[{{P}_{eff}}={{P}_{1}}+{{P}_{2}}\] Also we know, \[P=\frac{1}{f}\] Hence, \[{{P}_{eff}}=\frac{1}{{{f}_{1}}}+\frac{1}{{{f}_{2}}}=\frac{1}{0.20}+\frac{1}{0.25}=5+4=9D\]You need to login to perform this action.
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