The image formed by a spherical mirror is real and inverted and its magnification is -2 . If the image is at a distance of 30 cm from the mirror where is the object placed? Find focal length of the mirror. List any two characteristics of the image formed if the object is moved 10cm towards the mirror.
Answers
image distance = 30
magnification = -- 2
m= --v/u
-2 = -- 30/u
-2u = -- 30
u = -- 30/-- 2
u = 15
go and check comment please
in your question you say image is real and inverted but u is 15
so the object distanc is inside mirror ( In this case image is vitual and inverted)
plz check your question and comment
Answer:
Given :
Magnification m = - 2
Image distance v = 30 cm
We know :
m = - v / u
- 2 = - (- 30 ) / u
u = - 15 cm
We have mirror formula :
1 / f = 1 / v + 1 / u
1 / f = 1 / - 15 - 1 / 30
1 / f = - 1 / 10
f = - 10 cm
When the object is moved 10 cm towards the mirror.
Then : u' = u - 10 cm
= > u' = - 5 cm
Again putting in formula to get v'
1 / - 10 + 1 / 5 = 1 / v'
1 / v' = 2 - 1 / 10
v' = 10 cm
Therefore , the image is located 10 cm behind the mirror.
Also new magnification :
m' = -v' / u'
m' = - 10 / -5
m' = 2
Since magnification is positive the image is erect and virtual.
Also image is magnified in nature.