Question

An object of5cm in size is place on a distance 20cm from a concave mirror of focal length is 15cm what distance form the mirror should a stream deep place to get the sharp image also calculate the size of image​

Answer 1

Answer:

Sorry

Explanation:

Answer 2

Height of object ( h1 ) = 5cm.

Object distance( u ) = - 20cm.

( object is placed on the LHS )

Focal length ( f ) = - 15cm.

{ Focal length of concave mirror is negative } .

Image distance ( v ) = ?

And , Height of the image ( h2 ) = ?

From the mirror formula , we know that :

1/f = 1/v + 1/u.

1/-15 = 1/v + 1/-20.

1/v = -1/15 + 1/20.

( transposing ).

1/v = ( -4 + 3 )/60.

( LCM is 60 )

1/v = -1 /60

Therefore , v = -60cm.

Hence, the image will be obtained at a distance of 60cm in front of the mirror.

Now,

Magnification = - Image distance / Object distance .

m = -v /u.

m = -(-60) / -20.

m = 60 /-20 .

m = -3.

Now, we need to find out the height of the image ,

So, magnification = image height / object height.

-3 = h2 / h1

-3 = h2 / 5

h2 = -3 × 5.

h2 = -15.

Hence , the image is 15 cm in height .

Nature of the image:

Nature of the image:The image is real and inverted , it is larger than the object by a factor of 3. It is formed on the same side of the mirror.

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