Q. The sun (diameter $d$) subtends an angle $\theta$ radian at the pole of a concave mirror of focal length $f$. The diameter of the image of sun formed by mirror is
A) $\theta\ f$
B) $\frac{\theta}{2}\ f$
C) $2\theta\ f$
D) $\frac{\theta\ }{\pi\ }\ f$
Explanation
(a) $\frac{I}{d} = \frac{f}{u}$
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Or $I = \frac{d}{u}f\ $or$\ \ I = \theta f$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.