an object 4cm hight place at a distance of 20cm front of convex mirror of radius of curvature 60cm find the position nature and size of the imagery
Answers
Position of Image : Behind the mirror.
Nature of Image : Virtual and Erect.
Size of the Image: Diminished.
Explanation:
Given:
Height of object = 5 cm
Object Distance (u) = - 20 cm (By using Sign Convention)
Radius of Curvature (R) = 30 cm
Focal Length (f) = 2R = 30 / 2 = 15 cm (By using Sign Convention)
Using Mirror Formula:
{\boxed{\boxed{\sf{1/v + 1/u = 1/f}}}}
1/v+1/u=1/f
1/v - 1/20 = 1/15
1/v = 1/15 + 1/20
1/v = 4 + 3 / 60 (Taking LCM of 15 and 20)
1/v = 7 / 60
Image distance is 8.57 cm behind the convex mirror. As the v is positive the image formed is virtual and erect.
{\boxed{\boxed{\sf{Magnification = - v / u }}}}
Magnification=−v/u
= - 8.57 / - 20 = 0.4 cm
This indicates that the image is diminished because the magnification of the image is less than 1.
{\boxed{\boxed{\sf{Magnification = Height Of Object / Height Of Image}}}}
Magnification=HeightOfObject/HeightOfImage
= hi / ho = 0.4
We know ho here,
hi / 5 = 0.4
hi = 0.4 * 5
hi = 2 cm
As the image formed is smaller than the height of the object the image formed is diminished.
Therefore the final answer,
Position of Image : Behind the mirror.
Nature of Image : Virtual and Erect
Size of the Image: Diminished.