Question

An object of 5.0 cm in size is placed at a distance of 20.0 cm from a concave
mirror of focal length 15cm. At what distance from the mirror should a screen
be placed to obtain a sharp imge also calculate the size of image.
3​

Answer 1

Answer:hi sister idont know clearly about answer can you be as my friend

Answer 2

Answer:

Given,

Object Size (I) = 5 cm

Object Distance (u) = 20 cm (negative)

Focal Length (f) = 15 cm (negative)

∴ 1/f = 1/v+1/u

= - 1/15 =  1/v+(-1/20)

= -1/15 = 1/v-1/20

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

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

= -1/60 = 1/v

= -60 cm = v

[Value is negative which states that image is real]

Linear Magnification (m) = -(v/u)

= -(-60/-20)

= -3

Image Size = 5*3 cm

= 15 cm

The Screen must be placed at 60 cm from the Mirror and the Image will have a size/height of 15 cm.

I hope this helps.