MCQ
Two parallel pillars are $11\, km$ away from an observer. The minimum distance between the pillars so that they can be seen separately will be.....$m$
- ✓$3.2 $
- B$20.8$
- C$91.5$
- D$183$
✓
Answer
Correct option: A.
$3.2 $
a
(a) As limit of resolution of eye is ${\left( {\frac{1}{{60}}} \right)^o}$, the pillars will be seen distinctly if $\theta > {\left( {\frac{1}{{60}}} \right)^o}$
i.e., $\frac{d}{x} > \left( {\frac{1}{{60}}} \right) \times \frac{\pi }{{180}}$
$ \Rightarrow d > \frac{{\pi \times x}}{{60 \times 180}}$
$ \Rightarrow d > \frac{{3.14 \times 11 \times {{10}^3}}}{{60 \times 180}}$$ \Rightarrow d > 3.2\;m$
(a) As limit of resolution of eye is ${\left( {\frac{1}{{60}}} \right)^o}$, the pillars will be seen distinctly if $\theta > {\left( {\frac{1}{{60}}} \right)^o}$
i.e., $\frac{d}{x} > \left( {\frac{1}{{60}}} \right) \times \frac{\pi }{{180}}$
$ \Rightarrow d > \frac{{\pi \times x}}{{60 \times 180}}$
$ \Rightarrow d > \frac{{3.14 \times 11 \times {{10}^3}}}{{60 \times 180}}$$ \Rightarrow d > 3.2\;m$
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