- #1
good_phy
- 45
- 0
Hi, I studied concept of numerical aperture and f number
I learned numerical aperture(N.A) is measure of how much light can be entered into the
optical system, its mathematical expression is N.A = [tex]nsin\theta_m [/tex] where n is
index of refraction of immersing medium surrounding lens and [tex]\theta_m[/tex] is
maximum angle between optical axis and rim of lens.
I got a question. What is the point from which two line(one is from the point to rim of lens,
another is from the point along optical axis to lens) make maximum angle?
I think maximum angle is varying as the point moves along axis, So it is not clear for me.
And why can more light enter the optical system if n increases, causes N.A increase.
Please solve my question.
I learned numerical aperture(N.A) is measure of how much light can be entered into the
optical system, its mathematical expression is N.A = [tex]nsin\theta_m [/tex] where n is
index of refraction of immersing medium surrounding lens and [tex]\theta_m[/tex] is
maximum angle between optical axis and rim of lens.
I got a question. What is the point from which two line(one is from the point to rim of lens,
another is from the point along optical axis to lens) make maximum angle?
I think maximum angle is varying as the point moves along axis, So it is not clear for me.
And why can more light enter the optical system if n increases, causes N.A increase.
Please solve my question.