Which of a spherical mirror is 20 cm What is its focal length?

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

Radius of curvature, R= 20 cm
Radius of curvature of a spherical mirror = 2 × Focal length (f)R= 2f
f= R/2 = 20 / 2 = 10
Hence, the focal length of the given spherical mirror is 10 cm.

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Text Solution

Solution : Radius of curvature, R = 20 cm <br> Radius of curvature of a spherical mirror = 2 × Focal length (f) R <br> `f=R//2=20//2=10` <br> Hence, the focal length of the given spherical mirror is 10 cm.

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

Answer-

According to the question, radius of curvature (R) is 20 cm

Expression for radius of curvature of the spherical mirror is

= 2 × Focal length (f)

So, R = 2f

Or, f= R/2 = 20 / 2

f = 10

Therefore, focal length of the spherical mirror is 10 cm.