Question

if r=15 then calculate F value​

Answer 1

Provided that:

• R = 15

To calculate:

• f

Solution:

• Focal length, f = 7.5 unit

Using concept:

• Focal length formula

Using formula:

• Focal length formula:

• ${\small{\underline{\boxed{\pmb{\sf{f \: = \dfrac{R}{2}}}}}}}$

Where, f denotes focal length and R denotes radius of curvature.

Required solution:

$:\implies \sf Focal \: length \: = \dfrac{Radius \: of \: curvature}{2} \\ \\ :\implies \sf f \: = \dfrac{R}{2} \\ \\ :\implies \sf f \: = \dfrac{15}{2} \\ \\ :\implies \sf f \: = 7.5 \: unit \\ \\ :\implies \sf Focal \: length \: = 7.5 \: unit$

Additional information:

• If the magnification produced by a spherical mirror is in negative then the mirror is always “Concave Mirror.”

• If the magnification produced by a spherical mirror is in positive then the mirror is always “Convex Mirror.”

• If magnification is negative in a concave mirror then it's nature is “Real and Inverted” always.

• If magnification is positive then it's nature is “Virtual and Erect” always.

• If in the ± magnification, magnitude > 1 then the image formed is “Enlarged”.

• If in the ± magnification, magnitude < 1 then the image formed is “Diminished”.

• If in the ± magnification, magnitude = 1 then the image formed is “Same sized”.

• If the focal length is positive then the mirror is “Convex Mirror.”

• If the focal length is negative then the mirror is “Concave Mirror.”

• R = 2f

• f = R/2

• Where, f denotes focal length and R denotes radius of curvature.