Advertisements
Advertisements
Question
What is the relation between the focal length and radius of curvature of a spherical mirror (concave mirror of convex mirror)? Calculate the focal length of a spherical mirror whose radius of curvature is 25 cm.
Advertisements
Solution
The relation between the focal length and radius of curvature of a spherical mirror is as follows:
Radius of curvature = 2 x focal length
R = 2f
Given, the radius of curvature 'R' = 25 cm
Then, the focal length `f``=25/2 =12.5cm`
APPEARS IN
RELATED QUESTIONS
One half of a convex lens of focal length 10 cm is covered with a black paper. Can such a lens produce an image of a complete object placed at a distance of 30 cm from the lens? Draw a ray diagram to justify your answer. A 4 cm tall object is placed perpendicular to its principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image.
A student obtains a sharp image of the distant window (W) of the school laboratory on the screen (S) using the given concave mirror (M) to determine its focal length. Which of the following distances should he measure to get the focal length of the mirror?
Explain the following term related to spherical lenses:- principal focus
We can obtain a real, enlarged and inverted image by a concave mirror.
Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.
What is a virtual image?
Complete the following sentence:
All the distances are measured from the .......... of a spherical mirror.
What is a spherical mirror?
How is the focal length of a spherical mirror related to its radius
Name the two kinds of spherical mirrors and distinguish between them.
For an incident ray directed towards centre of curvature of a spherical mirror the reflected ray:
Select the correct option:
A concave mirror is made by cutting a portion of a hollow glass sphere of radius 30 cm. The focal length of the concave mirror is:
Define the following term:
spherical mirror
Define the term Principle focus.
The following Figure shows a concave mirror MM' on which a ray of light incident from a point P gets reflected to meet the principle axis at O.
(a) Find, by construction, the position of the centre of curvature of the concave mirror.
(b) Write down the value for the radius of curvature of the mirror.
(c) Calculate the focal length of the mirror.
(d ) Which relation is used in deducing the focal length from the radius of curvature?
How tall does a mirror have to be to fit an entire person’s body?
What is the focal length (f) of a mirror?
