Answer:
(a). The image distance is 13.77 cm to the left side of a lens.
(b). The magnification of the image is -0.655
Explanation:
Given that,
Object distance u= 21.0 cm
Focal length f= -40.0 cm
(a). We need to calculate the image distance
Using formula of lens
[tex]\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}[/tex]
Put the value into the formula
[tex]\dfrac{1}{-40}=\dfrac{1}{v}-\dfrac{1}{-21}[/tex]
[tex]\dfrac{1}{v}=\dfrac{1}{-40}+\dfrac{1}{-21}[/tex]
[tex]\dfrac{1}{v}=-\dfrac{61}{840}[/tex]
[tex]v=-13.77\ cm[/tex]
(b). We need to calculate the magnification of the image
Using formula of magnification
[tex]m=-\dfrac{v}{u}[/tex]
Put the value into the formula
[tex]m=-\dfrac{13.77}{21.0}[/tex]
[tex]m=-0.655[/tex]
Hence, (a). The image distance is 13.77 cm to the left side of a lens.
(b). The magnification of the image is -0.655
