What is the position nature and size of the image formed by a concave mirror when the object is at C the center of curvature of the mirror?

Edited by Sim, Jen Moreau

Índice Show

Object between infinity and Centre of Curvature:
Object between Centre of curvature (C) and Principal Focus (F):
Object between Principal Focus (F) and Pole (P):

Is defined as a spherical mirror with a polished inner side.

The type of images formed by a concave mirror depends on the position of the object to the mirror. If the distance of an object say OO' from a concave mirror is changed, then the nature, size, and location of the image are also changed.

Was this helpful? Yes | No| I need help

Formation of different images depending on the position of the object are shown below:.

If you need to reference this article in your work, you can copy-paste the following depending on your required format:

APA (American Psychological Association)
Concave Mirrors. (2017). In ScienceAid. Retrieved Nov 21, 2022, from https://scienceaid.net/Concave_Mirrors

MLA (Modern Language Association) "Concave Mirrors." ScienceAid, scienceaid.net/Concave_Mirrors Accessed 21 Nov 2022.

Chicago / Turabian ScienceAid.net. "Concave Mirrors." Accessed Nov 21, 2022. https://scienceaid.net/Concave_Mirrors.

Comments

Categories : Physics

Recent edits by: Sim

Formation of image depends upon the position of the object. There are six possibilities of the position of object in the case of concave mirror.

Since parallel rays coming from the object converge at principal focus, F of a concave mirror; after reflection. Hence, when the object is at infinity the image will form at F.

Fig: Object at Infinity

Properties of image:

Point sized
Highly diminished
Real and inverted

Object between infinity and Centre of Curvature:

When object is placed between infinity and centre of curvature of a concave mirror the image is formed between centre of curvature (C) and focus (F).

Fig: Object Between Infinity and C

Properties of image:

Diminished compared to object
Real and inverted

When the object is placed at centre of curvature (C) of a concave mirror, a real and inverted image is formed at the same position.

Fig: Object at C

Properties of image:

Same size as object
Real and inverted

Object between Centre of curvature (C) and Principal Focus (F):

When the object is placed between centre of curvature and principal focus of concave mirror, a real image is formed beyond the centre of curvature (C).

Fig: Object between C and F

Properties of image:

Larger than object
Real and inverted

When the object is placed at principal focus (F) of a concave mirror, a highly enlarged image is formed at infinity.

Fig: Object at F

Properties of image:

Highly enlarged
Real and inverted

Object between Principal Focus (F) and Pole (P):

When the object is placed between principal focus and pole of a concave mirror, an enlarged, virtual and erect image is formed behind the mirror.

Fig: Object between F and P

Properties of image:

Enlarged
Virtual and erect

Positions of Object and Image in Concave Mirror
Position of Object	Position of Image	Size of Image	Nature of Image
At infinity	At focus	Point sized, highly diminished	Real and inverted
Between infinity and C	Between F and C	Dminished	Real and inverted
At C	At C	Same size	Real and inverted
Between C and F	Beyond C	Enlarged	Real and inverted
At F	At infinity	Highly enlarged	Real and inverted
Between F and P	Behind mirror	Enlarged	Virtual and erect

3. Find the size, nature and position of image formed when an object of size 1 cm is placed at a distance of 25 cm from a concave mirror of focal length 20 cm ?

Sol: Here we have been given the object distance and focal length, so first of all we will find out the image distance which will give us the position of image.

(i) Position of image

Here, Object distance, u	=	− 25 cm (To the left of mirror)
Image distance, v	=	? (To be calculated)
And, Focal length, f	=	− 20 cm (It is concave mirror)
Now, putting these values in the mirror formula :
1/f	=	1/v + 1/u
We get: 1/–20	=	1/v + 1/– 25
(or) – 1/20	=	1/v – 1/25
(or) 1/v	=	1/25 – 1/20
	=	4 – 5/100
	=	– 1/100
So Image distance, v	=	− 100cm

Thus, the position of image is 100 cm to the left side of mirror or 100 cm in front of mirror (Minus sign shows the left side of mirror).

(ii) Nature of image

Since the image is formed in front of the concave mirror, its nature will be “Real and Inverted”.

(iii) Size of image

To find the size of image, we will have to calculate the magnification first.

The magnification produced by a mirror is given by :
m	=	v/u
Here Image distance, v	=	− 100cm
Object distance, u	=	− 25cm
So, m	=	– (–100) / (– 25) = –4
Magnification,m	=	−4
We also have another formula for magnification, which is :
m	=	h2/h1
Here, Magnification,m	=	−4 (Found above)
Height of image,h2	=	? (To be calculated)
Height of object,h1	=	1cm (Given)
Now, putting these values in the above magnification formula, we get:
– 4	=	h2/1