Advertisements
Advertisements
Question
What is meant by magnification? Write its expression. What is its sign for real image and virtual image?
Advertisements
Solution
Magnification produced by a spherical mirror gives how many times the image of an object is magnified with respect to the object size.
It can be defined as the ratio of the height of the image (hi) to the height of the object (ho).
Magnification = m = `"hi"/"ho"= "height of the image"/"height of the object"`
- for real image it is negative,
- for virtual image it is positive.
APPEARS IN
RELATED QUESTIONS
A student wants to project the image of a candle flame on a screen 90 cm in front of a mirror by keeping the flame at a distance of 15 cm from its pole.
(a) Suggest the type of mirror he should use.
(b) Determine the linear magnification in this case.
(c) Find the distance between the object and its image.
(d) Draw ray diagram to show the image formation in this case
The image formed by a concave mirror is real, inverted and of the same size as the object. The position of the object must then be:
(a) at the focus
(b) between the centre of curvature and focus
(c) at the centre of curvature
(d) beyond the centre of curvature
According to New Cartesian Sign Convention:
(a) focal length of concave mirror is positive and that of convex mirror is negative
(b) focal length of both concave and convex mirrors is positive
(c) focal length of both concave and convex mirrors is negative
(d) focal length of concave mirror is negative and that of convex mirror is positive
A virtual, erect and magnified image of an object is to be obtained with a convex lens. For this purpose,the object should be placed:
(a) between 2F and infinity
(b) between F and optical centre
(c) between F and 2F
(d) at F
What is the nature of the image formed by a convex lens if the magnification produced by the lens is, – 0.5?
A small object is so placed in front of a convex lens of 5 cm focal length that a virtual image is formed at a distance of 25 cm. Find the magnification.
Determine how far an object must be placed in front of a converging lens of focal length 10 cm in order to produce an erect (upright) image of linear magnification 4.
An object placed 4 cm in front of a converging lens produces a real image 12 cm from the lens.
(a) What is the magnification of the image?
(b) What is the focal length of the lens?
(c) Draw a ray diagram to show the formation of image. Mark clearly F and 2F in the diagram.
Magnification produced by a rear view mirror fitted in vehicles ______.
What is the nature of the image formed by a concave mirror if the magnification produced by the mirror is +4?
