Answer:
P = 1 D
f = 1 m = 100 cm
Explanation:
The power of the combination of lenses is simply found out by adding the power of the individual lens:
[tex]P = P_{1}+P_{2}[/tex]
where,
P = Power of combination of lenses = ?
P₁ = Power of first lens = 3.5 D
P₂ = Power of second lens = -2.5 D
Therefore,
[tex]P = 3.5\ D - 2.5\ D[/tex]
P = 1 D
Now, for focal length:
[tex]Focal\ Length = f = \frac{1}{D}\\\\f = \frac{1}{1\ D}[/tex]
f = 1 m = 100 cm
