Explanation:
Image distance, v = -17 cm (-ve for virtual image)
Radius of curvature of concave mirror, R = 39 cm
Focal length, f = -19.5 cm (-ve for a concave mirror)
(a) Using mirror's formula as :
[tex]\dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f}[/tex]
[tex]\dfrac{1}{u}=\dfrac{1}{f}-\dfrac{1}{v}[/tex]
[tex]\dfrac{1}{u}=\dfrac{1}{-19.5}-\dfrac{1}{(-17)}[/tex]
u = 132.6 cm
So, the object is placed 132.6 cm in front of the mirror.
(b) Magnification of the mirror, [tex]m=\dfrac{-v}{u}[/tex]
[tex]m=\dfrac{-17}{132.6}[/tex]
m = -0.128
Hence, this is the required solution.
