Question

An object 4 cm in height,is placed at 15 CM in front of a concave mirror of focal
length 10cm .at what distance from the mirror should a screen be placed to obtain
a sharp image of the object? calculate the height of the image.

Answer 1

Step-by-step explanation:

Given that

-u=-15cm ( object distance is negative in concave mirror)

f=-10cm( focal length is also negative in concave mirror)

height of object =4cm

formula we use is,

1/f=1/v+1/u

1/-10=1/v+1/-25

1/v=-1/10+-1/25

1/v=-2+5/250

1/v=-3/250

v=-250/3

v=-83.3cm

to find height of image

hi/ho=-v/u

hi/4=-(-83.3)/-15

=(-83.3)×4/15

=-333.2/15

hi=22.213cm