Question

2. An object is placed 15cm from a concave mirror of radius of curvature 60 cm. Find the
position of image and its magnification?
3.
An object is kept at a distance of 5cm in front of a convex mirror of focal length 10cm. Give
the position, magnification and the nature of the image formed. class10 ​

Answer 1

Answer:

• f = R/2

=> f = -60/2

=> f = -30 cm

Now,

=> 1/v + 1/u = 1/f

=> 1/v + 1/(-15) = -1/30

=> 1/v - 1/15 = 1/30

=> 1/v = -1/30 + 1/15

=> 1/v = -1+2/30

=> 1/v = 1/30

=> 1/v = 1/30

=> v = 30 cm

Position is 30 cm.

Answer 2

[1]

$\huge {\underline{\pink{Given:-}}}$

• Object distance ,u = -15 cm

•Radius of Curvature ,R = -60cm

$\huge {\underline{\green{To Find:-}}}$

• Position of Image,v

• Magnification ,m

$\huge {\underline{\blue{Solution:-}}}$

Firstly we calculate the Focal length of the mirror. As we know relationship between Focal length and Radius of Curvature.

• f = R/2

Substitute the value we get

→ f = -60/2

→ f = -30 cm

Now, Using Mirror Formula

• 1/v + 1/u = 1/f

Substitute the value we get

→ 1/v + 1/(-15) = -1/30

→ 1/v - 1/15 = 1/30

→ 1/v = -1/30 + 1/15

→ 1/v = -1+2/30

→ 1/v = 1/30

→ 1/v = 1/30

→ v = 30 cm

Therefore, the position of the image is 30 cm from the object.

Now, Calculating Magnification

• m = -v/u

Substitute the value we get

→ m = -30/-15

→ m = 2

Therefore, the magnification of the image is 2

______________________________

[2]

$\huge {\underline{\pink{Given:-}}}$

• object distance ,u = -5 cm

• focal length ,f = 10 cm

$\huge {\underline{\green{To Find:-}}}$

• Position &and ; Nature of Image

• Magnification ,m

$\huge {\underline{\blue{Solution:-}}}$

Using mirror formula

• 1/v + 1/u = 1/f

Substitute the value we get

→ 1/v + 1/(-5) = 1/10

→ 1/v -1/5 = 1/10

→ 1/v = 1/10 + 1/5

→ 1/v =1+2 /10

→ 1/v = 3/10

→ v = 10/3

→ v = 3.33 cm

Therefore, the image position is 3.33 cm from the mirror.

Now, calculating the Magnification

• m = -v/u

Substitute the value we get

→ m = -3.33/-5

→ m = 3.33/5

→ m = 0.66

Therefore, the magnification of the mirror is 0.66 .The image formed is Virtual and erect