define the following terms for both concave and convex mirrors and how are they denoted a)centre of curvature b)pole c) radius of curvature d)aperture e)focus f)focal length g) relation between focal length and radius of curvature
Answers
Physics > Light - Reflection and Refraction > Terms Related to Spherical Mirrors
Light - Reflection and Refraction
Terms Related to Spherical Mirrors
“Mirror, mirror on the wall, who’s the fairest of them all?” We’ve all heard this dialogue from the story of Snow white and the seven dwarfs. But what kind of mirror was it? What were the properties that enabled these spherical mirrors to be so special? Well, let us find answers to it in this section.
There’re few basic and important terms one needs to know while studying spherical mirrors inside the chapter “Reflection and Refraction”:
a. Center of Curvature (c)
b. Radius of Curvature (r)
c. Pole (p)
d. Principal axis
e. Aperture
f. Principal Focus or Focal Length
g. Focus
a. Center of Curvature (c) :
(Source: Wikipedia)
The Center of Curvature of a spherical mirror is the point in the centre of the mirror which passes through the curve of the mirror and has the same tangent and curvature at that point. It is denoted by the letter ‘c’.
b. Radius of Curvature (r):
It’s the linear distance between Pole and the Center of curvature.
c. Pole (p) :
It’s the midpoint of the spherical mirror.
d. Principal axis:
It’s an imaginary line passing through the optical centre and the centre of curvature of any lens or a spherical mirror.
e. Aperture:
An aperture of a mirror or lens is a point from which the reflection of light actually happens. It also gives the size of the mirror.
f. Principal Focus :
Principal Focus can also be called as Focal Point. It’s on the axis of a mirror or lens wherein rays of light parallel to the axis converge or appear to converge after reflection or refraction. Principal Focus is also what determines the Focal Length of the mirror.
g. Focus:
It’s any given point, where light rays parallel to the principal axis, will converge after getting reflected from the mirror.
What is an Image?
When an object is placed in front of a mirror, we see an image of the object placed. This image appears to be behind the mirror, and is called “Image”. The object is the source from which incident ray occurs and the image that is formed is because of the reflected rays. The image formed maybe “Real” or “Virtual”.