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As shown in the figure, a paraxial ray is incident
at point Q on a concave mirror.
q = angle of incidence = angle of reflection
= Ð CQF = Ð QCF ( by geometry )
So, for D CFQ,
exterior Ð QFP = Ð CQF + Ð QCF = 2q .
For paraxial incident ray and small aperture,
CP' » CP = R and FP' » FP = f.
For small aperture, 2q is very small.
\ from the figure, 2q »
FP
QP
=
f
QP
… ( 1 ) and q =
CP
QP
=
R
QP
… ( 2 )
From equations ( 1 ) and ( 2 ), R = 2f ⇒ f = R / 2
Thus, focal length of a concave mirror is half its radius of curvature.
What else can I help you with?
What is the relationship between the radius of curvature and focal length in a concave mirror?
In a concave mirror, the radius of curvature is twice the focal length.
What is the focal length of concave mirror of radius 20cm?
The focal length of a concave mirror is half of its radius of curvature. Therefore, for a concave mirror with a radius of 20 cm, the focal length would be 10 cm.
What is a concave mirror has a radius of curvature of 40.5 cm. how far is the mirror from the persons face?
The focal length of a mirror with a radius of curvature of 40.5 cm is half of the radius, so it is 20.25 cm. The mirror's face would be placed around this focal length distance from the person's face for optimal viewing.
For very small angles the focal length of a concave mirror is?
For very small angles, the focal length of a concave mirror is approximately half of the radius of curvature of the mirror. This is known as the mirror equation and holds true for small angles under the paraxial approximation.
What is the focal length of concave mirror to form real image?
The focal length of a concave mirror to form a real image is positive. It is equal to half the radius of curvature (R) of the mirror, and the image is formed between the focal point and the mirror.
What is the relationship between the radius of curvature and focal length in a concave mirror?
In a concave mirror, the radius of curvature is twice the focal length.
What is the focal length of concave mirror of radius 20cm?
The focal length of a concave mirror is half of its radius of curvature. Therefore, for a concave mirror with a radius of 20 cm, the focal length would be 10 cm.
What is the relation between focal length and center of curvature?
The focal length of a concave mirror is about equal to half of its radius of curvature.
If the focal lenght of a concave mirror is 15 cm find the radius of curvature?
The radius of curvature and the focal length mean the same so the radius of curvature is also 15 cm.
What is a concave mirror has a radius of curvature of 40.5 cm. how far is the mirror from the persons face?
The focal length of a mirror with a radius of curvature of 40.5 cm is half of the radius, so it is 20.25 cm. The mirror's face would be placed around this focal length distance from the person's face for optimal viewing.
For very small angles the focal length of a concave mirror is?
For very small angles, the focal length of a concave mirror is approximately half of the radius of curvature of the mirror. This is known as the mirror equation and holds true for small angles under the paraxial approximation.
Why the focal length of concave mirror changes in water?
I don't think so. The focal length would remain the same. It mainly depends on the radius of curvature of the mirror.
What is the focal length of concave mirror to form real image?
The focal length of a concave mirror to form a real image is positive. It is equal to half the radius of curvature (R) of the mirror, and the image is formed between the focal point and the mirror.
What is the Focal length of a concave mirror?
It is the point , on the central axis, where light, that is parallel to the central axis, passes thru after it is reflected from the mirror. It is also at a distance from the mirror equal to twice the radius of curvature of the mirror.
The relation between focal length and radius of curvature of spherical mirror is?
The relation between focal length (f), radius of curvature (R), and the focal point of a spherical mirror can be described by the mirror equation: 1/f = 1/R + 1/R'. The focal length is half the radius of curvature, so f = R/2.
Will focal length of a concave mirror would increase decrease stay the same if the mirror were made flatter?
If a concave mirror is made flatter, its focal length will increase. This is because a flatter mirror has a larger radius of curvature, resulting in light rays converging at a point farther away from the mirror.
Is the focal length equal to the radius of curvature of the mirror?
yes
