The focal length of the lens is 2m and the position of the image is 6 m.
The size of the image formed depends on the position of the object from the lens.
[tex]M = \frac{v}{u}[/tex]
where;
The image distance is calculated as follows;
[tex]2 = \frac{v}{3} \\\\v = 2(3) \\\\v = 6 \ m[/tex]
The focal length of the lens is calculated as follows;
[tex]\frac{1}{f} = \frac{1}{v} + \frac{1}{u}\\\\\frac{1}{f} = \frac{1}{6} + \frac{1}{3} \\\\\frac{1}{f} = \frac{3}{6} \\\\f = 2m[/tex]
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