Question

The angle subtended by a coin of radius $1 \,cm$ held at a distance of $80 \,cm$ from your eyes is

• A. $ 1.43^{\circ} $
• B. $ 0.72^{\circ} $
• C. $ 0.0125^{\circ} $
• D. $ 0.025^{\circ} $

Answer 1

Answer: (A)

Let angle subtended by coin at the eye be $6$.
$ \sin \theta \simeq \frac{D}{L} $
Here, $ D=2r=2\times 1=2\,\,cm $
$ L=80\,\,cm $
$ \therefore $ $ \theta =\frac{2}{80}=0.025 $ rad
$ =1.43^{\circ} $