Question

An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed, so that a sharp focussed image can be obtained? Find the size and the nature of the image.

Answer 1

$\textbf{Answer is in Attachment !}$

Answer 2

Olá!!
Here's the answer.

✴ The object distance, u = -27 cm.

The image distance, v = ?

The focal length, f = - 18 cm.

✴ Then according to mirror formula,

✳ 1/f = 1/v +1/u.
✳ 1/f - 1/u = 1/v.
✳ 1/-18 - 1/-27 = 1/v.
✳ 1/-18 + 1/27 = 1/v.
✳ -3+2/54 = 1/v.
✳ -1/54 = 1/v.
✳ v = -54 cm.

Therefore, image distance, v = -54 cm.

✴ Now, As given in question,
The size of object is -7.0 cm.

✴ Therefore,

✳ m = h'/h = -v/u.
✳ h'/h = -v/u.
✳ h'/7 = -(-54)/-27.
✳ h' = -2×7.
✳ h' = -14 cm.

✴ Therefore, the size of image = -14 cm.

• IMAGE IS REAL AND INVERTED.

Hope it helps!!
@charlie16.
#BeBrainly.