JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
What is the relative decrease in focal length of a lens for an increase in optical power by 0.1 D from 2.5D ? ['D' stands for dioptre]
- A \(0.01\)
- B \(0.04\)
- C \(0.40\)
- D \(0.1\)
Answer & Solution
Correct Answer
(B) \(0.04\)
Step-by-step Solution
Detailed explanation
\begin{aligned} & P=\frac{1}{f} \\ & \text { So } P_1=\frac{1}{F_1} \Rightarrow F_1=\frac{1}{2.5} \\ & \text { Next } F_2=\frac{1}{2.6} \\ & \left|\frac{\Delta F}{F_1}\right|=\frac{\left|F_2-F_1\right|}{F_1}=\left|\frac{F_2}{F_1}-1\right| \\ & \Rightarrow\left|\frac{\Delta…
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