Q. Sun subtends an angle of $0.5{^\circ}$ at the centre of curvature of a concave mirror of radius of curvature 15 m. The diameter of the image of the sum formed by the mirror is
A) 8.55 cm
B) 7.55 cm
C) 6.55 cm
D) 5.55 cm
Explanation
(c) $\theta = \frac{1}{2} \times \frac{\pi}{180}\ $rad
$\frac{diametar\ of\ image}{focal\ length} = \theta$
Or diameter of image
$= \frac{1}{2} \times \frac{\pi}{180} \times \frac{15}{2} \times 100\ cm = 6.55\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.