Question

17. (i) An object having size 2 cm, placed 10 cm in front of a concave mirror having focal length 8 cm.
Calculate the position, nature and size of Image.
(ii) Write down one application of each concave mirror and convex mirror.
5​

Answer 1

(i)

GIVEN:

object distance,u= –10cm

focal length,f =+8cm

height of object,h¹

Image distance=?

To solve the question we should mirror formula:

1/V + 1/U = 1/f

1/V+1/-10= 1/+8

1/V–1/+10= 1/8

1/V= 1/8+1/10

on find the lcm of 8 and 10 we get 2×2×2×5 I.e. 40

so,

1/V=9/40

9v=40

now, V/ image distance =40/9

=+4.5cm

Now to find the size of image we need to apply magnification formula I.e.

magnification,m = –V/U

we have u = -10

v = +4.5

Now putting the values:

m= –(+4.5) / (-10)

m=+0.45

We also have another magnification formula:

m=h²/h¹

we have m=+0.45, height of object,h¹=+2cm

so,

0.45=h²/+2

h²=0.45×2

h²/height of image=+0.9

HENCE:

● the position of image is +4.5 cm

● the height of image is +0.9

●The nature of the image is virtual and erect

(ii)

Application of concave mirror:

▪︎These mirrors are used as shaving mirrors to see the large image of face.

Application of convex mirror:

▪︎These mirrors are used as rear view mirrors in vehicles to see the traffic at back side in a wide range.

HOPE U LIKE IT.