Question

an object of heuhght is placed at 20 cm duatance in fornt of a concave mirrir whose focal length is 15 cm calculate height of the image​

Answer 1

Answer:

Hey there !

Explanation:

Let height of the object be H1 and height of the image be H2

Given the focal length is = -15cm

Also,Oject distance ie. u = -20cm

Image distance ie. v is unknown.

Using mirror formula

1/f = 1/v +1/u

=> 1/(-12)= 1/v + 1/(-20)

=> 1/v = -2/60

=> v = -30cm

Now , magnification(M) = H2/H1= -v/u

=30/(-20)

=-1.5

So, so H2= 1.5 x H1

Since the value of H1 ie size of object is not mentioned in your question, hence the the value of H2 ie height of image cannot be calculated. However in case, it is mentioned in the question, you can calculate it in this way.

Hope that helps !! :)