Advertisements
Advertisements
प्रश्न
Define the following term in relation to concave mirror.
Focal length
Advertisements
उत्तर
The linear distance between the pole and the principal focus is called focal length.
APPEARS IN
संबंधित प्रश्न
Explain the following term related to spherical lenses:- principal focus
What is a virtual image?
A ray of light is incident normally on a plane mirror. What will be the
angle of incidence?
Write the formula for a lens connecting image distance (v), object distance (u) and the focal length (f). How does the lens formula differ from the mirror formula?
State the two kinds of spherical mirror and distinguish them with the aid of proper diagrams.
An optical device has been given to a student and he determines its focal length by focusing the image of the sun on a screen placed 24 cm from the device on the same side as the sun. Select the correct statement about the device.
(A) Convex mirror of focal length 12 cm
(B) Convex lens of focal length 24 cm
(C) Concave mirror of focal length 24 cm
(D) Convex lens of focal length 12 cm
Name the mirror which always produces an erect and virtual image. How is the size of image related to the size of object?
At what distance from a concave mirror of focal length 25 cm should an object be placed so that the size of image is equal to the size of the object.
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?
