The focal length of the lens = 24 cm
The magnification of the pug = 0.25
Explanation:The height of the pug = 30 cm
The pug's distance from the convex lens, u = 120 cm
The image distance from the convex lens, v = 30 cm
Calculate the focal length using the equation below
[tex]\frac{1}{f}=\frac{1}{u}+\frac{1}{v}[/tex]Substitute u = 120 cm, v = 30 cm, and solve for f
[tex]\begin{gathered} \frac{1}{f}=\frac{1}{120}+\frac{1}{30} \\ \frac{1}{f}=\frac{1+4}{120} \\ \frac{1}{f}=\frac{5}{120} \\ f=\frac{120}{5} \\ f=24\text{ cm} \end{gathered}[/tex]The focal length of the lens = 24 cm
The magnification of the pug = v/u
Magnification = 30/120
Magnification = 0.25
The magnification of the pug = 0.25
