Question

what is the focal length of a lens whose radius of curvature is 30 cm.​

Answer 1

Answer:

Radius of curvature R = 30 cm

Radius of curvature = 2 × Focal length (f)

R = 2 f

Hence, the focal length of the given convex mirror is 16 cm.

Answer 2

The focal length of a lens whose radius of curvature is 30 cm is 15cm.

• The focal length is half of the radius of curvature.
• 2× focal length = radius of curvature.
• Focal length is used to measure power and the type of lens.
• The power of the lens is the capacity of the lens to focus and bend the light rays properly when light falls on it. the higher the focal length lower will be power.
• SI unit of power is Diopters (D).
• Power is measured as the inverse of focal length. power is calculated in metres.
• $power \: = \frac{1}{f} \\ f is the \: focal \: length \: in \: metes$.

Henceforth, the focal length of the lens is 15 cm.