Question

The radius of curvature of a mirror is 40cm its focal length is * 1 point (a) 10cm (b) 80cm (c) 8cm (d) 40cm​

Answer 1

• Radius of curvature=40cm
• Focal length=?

We know

$\boxed{\sf R=2f}$

• R denotes to radius of curvature
• f denotes to focal length

$\\ \sf\longmapsto Focal\:Length=\dfrac{R}{2}$

$\\ \sf\longmapsto Focal\:Length=\dfrac{40}{2}$

$\\ \sf\longmapsto Focal\:Length=20cm$