- #1
UchihaClan13
- 145
- 12
Alright I was doing some basic questions on ray optics when this doubt came to my mind
So my doubt goes like this:(IT may be silly)
Consider a concave mirror with pole P and centre of curvature C
Its principal axis is extended on both sides
Now consider a ray parallel to the principal axis
Call this ray BA (it strikes the concave mirror at A)
Now assume it makes an angle 60 degrees with the normal
Thus as per the laws of reflection,angle BAC=angle CAF(a ray parallel to the principal axis passes through the principal focus after reflection
Then angle ACF=60 degrees(as BA is parallel to the principal axis thus due to alternate interior angles they are equal)
Which results in angle CFA=60 degrees(as CAF is a triangle)
As all angles are equal ,CAF should be an equilateral triangle
However CA=2CF(since CA is the radii of curavture and CF=FP which is the focal length)
This violates the condition for an equilateral triangle
I tried to solve this paradox but am still getting confused
Some help or insight would be much appreciated
Thanks
So my doubt goes like this:(IT may be silly)
Consider a concave mirror with pole P and centre of curvature C
Its principal axis is extended on both sides
Now consider a ray parallel to the principal axis
Call this ray BA (it strikes the concave mirror at A)
Now assume it makes an angle 60 degrees with the normal
Thus as per the laws of reflection,angle BAC=angle CAF(a ray parallel to the principal axis passes through the principal focus after reflection
Then angle ACF=60 degrees(as BA is parallel to the principal axis thus due to alternate interior angles they are equal)
Which results in angle CFA=60 degrees(as CAF is a triangle)
As all angles are equal ,CAF should be an equilateral triangle
However CA=2CF(since CA is the radii of curavture and CF=FP which is the focal length)
This violates the condition for an equilateral triangle
I tried to solve this paradox but am still getting confused
Some help or insight would be much appreciated
Thanks