Answer: -10

Explanation:

according to the given question , we know that the mirror formula is

1/f = 1/v + 1/u ---------(1)

where f → focal length = -20 cm

v → image distance

u→object distance

now, according to the given question

hi / ho = - V/U = 2

⇒ hi = 2ho also v = -2u

since we got v = -2u -----(2)

now by substituting equation (2) in (1) gives

⇒ -1/20 = -1/2u + 1/u

⇒ -1/20 = -1 + 2 / 2u

⇒ -1/20 = 1/2u

⇒ 2u = - 20

⇒ u = -10 cm

Verified answer

Answer:

Solution

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Correct option is A)

The focal length of the mirror is 20cm.

In the case of real image,

The object distance is u

1

, then the image distance will be −2u

1

.

The mirror formula is given as,

v

1

+

u

1

=

f

1

−2u

1

1

−

u

1

1

=

20

−1

u

1

=30cm

In the case of virtual image,

The object distance is −u

2

, then the image distance will be 2u

2

.

The mirror formula is given as,

v

1

+

u

1

=

f

1

2u

1

1

+

−u

1

1

=

20

−1

u

2

=10cm

The distance between two positions of object is given as,

u=30−10

=20cm

Thus the distance between the two positions of object is 20cm.

thanks for this .....❤️