Question

9.The radius of curvature of a spherical mirror is 20 cm. What is its focal
length?​

Answer 1

r=2f

20/2=f

f=10cm

hope u got ur answer

Answer 2

Answer:

R= 2f

f= R/2

$f = \frac{r}{2} = \frac{20}{2} = 10cm.$