Question

a 1.8 CM needle is placed 16 cm away from a convex mirror of focal length 20 CM give the location of the image and the magnification​

Answer 1

mirror formula=

$\frac{1}{i mage \: distance} + \frac{1}{object \: distance} = \frac{1}{focal \: length}$

therefore...
1/ v + 1/16 = 1/20
1/v = 1/20 - 1/16
1/v = 4/80 - 5/80
1/v = -1/80

so...
v = 80
magnification = height of image / height of object
= -v/u
therefore....
-80/16
= -5

magnification= -5

I guess this is right answer...