Question

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2) An object is placed 10cm in front of a concave mirror
of radius of curvature 16cm. The image will be formed at
(a) + 30cm (b)-30cm (0) +40cm col-40cm.​

Answer 1

Answer :-

v = - 40 cm

Solution :-

For a concave mirror

Object distance ( u ) = - 10 cm

Radius of curvature = - 16 cm

Focal length ( f ) = - 16 / 2 = - 8

Let the image distance be 'v' cm

Using mirror formula

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

==> 1 / ( - 8 ) = 1 / v + 1 / ( - 10 )

==> - 1 / 8 = 1 / v - 1 / 10

==> - 1 / 8 + 1 / 10 = 1 / v

==> ( - 10 + 8 ) / 80 = 1 / v

==> - 2 / 80 = 1 / v

==> v = - 80 / 2

==> v = - 40

Therefore the image will be formed at ( d ) - 40 cm.

Answer 2

$\huge\underline\bold\green{Answer:-}$

Given that u = 10cm and R= 16cm. So,

f= R/2

f=16/2

=-8 (as the focal length of concave mirror is negative).

Now applying the mirror formula:

1/v + 1/u= 1/f

1/v + 1/(-10) = 1/-8

1/v = 1/-8 + 1/10

1/v = (-10 + 8)/80

1/v = -2 / 80

1/v = -1/40

or v = -40cm

Hence the image will be formed at (-40) cm.