Advertisements
Advertisements
Question
An object of length 4 cm is placed in front of a concave mirror at distance 30 cm. The focal length of mirror is 15 cm.
- Where will the image form?
- What will be the length of image?
Advertisements
Solution
O = 4 cm
u = -30 cm
f = -15 cm
From mirror formula ,
`1/"f" = 1/"v" + 1/"u"`
∴ `1/"v" = 1/"f" - 1/"u"`
∴ `1/"v" = 1/(-15) - 1/(-30) = 1/30 - 1/15`
∴ `1/"v" = (-1)/30`
∴ v = -30 cm
Hence , the image is formed at a distance of 30 cm in front of the mirror .
m = `-"v"/"u" = "I"/"O"`
∴ I = `"-OV"/"u" = (-4 xx -30)/(-30) = -4`cm
Negative sign indicates inverted image.
So, I = 4 cm
Hence , the length of the image is 4 cm.
APPEARS IN
RELATED QUESTIONS
A ray of light is incident normally on a plane mirror. What will be the
angle of incidence?
A diverging lens is used in:
(a) a magnifying glass
(b) a car to see objects on rear side
(c) spectacles for the correction of short sight
(d) a simple camera
A ray of light travels from a denser medium to a rarer medium. How will it bend?
Three mirrors are created from a single sphere. Which of the following - pole, centre of curvature, radius of curvature, principal axis - will be common to them and which will not be common?
Define the terms pole, principal axis and centre of curvature with reference to a spherical mirror.
Define the following term in relation to concave mirror.
Aperture
Define the term Principle focus.
Size of image of an object by a mirror having a focal length of 20 cm is observed to be reduced to 1/3rd of its size. At what distance the object has been placed from the mirror? What is the nature of the image and the mirror?
What is the focal length (f) of a mirror?
