Question

The sun subtends an angle half a degree at the pole of a concave mirror which has a radius of curvature of 15 m. Then the size (diameter) of the image of sun formed by the convace mirror is
A. 7.5 cm
B. 6.55 cm
C. 3.5 cm
D. 1.31 cm

Answer 1

Correct Answer - B

`theta=((1)/(2))^0=((1)/(2))/(180)pi=(pi)/(360)rad`
The image of sun is formed at focus.
`theta=(d)/(f)impliesd=ftheta=(15)/(2)xx(pi)/(360)=0.0654m`
`=6.54cm`