If the centre of curvature a concave mirror is situated at 44cm, then find the focal length of the mirror.
Answers
The distance from the pole to the focal point is called the focal length (f). The focal length of a spherical mirror is then approximately half its radius of curvature. It is important to note up front that this is an approximately true relationship
The relationship between the radius of curvature and focal length is that the radius of curvature is twice the focal length.
In this case, focal length of the concave mirror is given as 15 cm. Hence, the radius of curvature is 15×2=30 cm.
When the object is placed on the centre of curvature, on the principal axis, in front of a concave lens, the image is formed at the same point. The image formed is real and inverted.
So, in this case, the object distance is equal to the image distance.
Therefore, the object size is equal to the image size.
As the object is of 4 cm in length, the image will also be of 4 cm in length.