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Lenses in contact
1/F = 1/f₁ + 1/f₂
Where: F = force (N), f₁ = f₁, f₂ = f₂
Solved example
Given: f_1 = 7, f_2 = 5
Find: F (force (N))
- Formula: 1/F = 1/f₂ + 1/f₁
- Rearranged for F: F = f₁·f₂/(f₁ + f₂)
- Substitute the values: F = 5·7/(5 + 7)
- Result: F = 2.916667
Answer: F = 2.916667
Calculator
How to calculate Lenses in contact
- Write down the formula: 1/F = 1/f₁ + 1/f₂.
- Note the known values (f₁, f₂).
- Substitute them and simplify to find F.
- Use the calculator above to solve for any letter.
Frequently asked questions
What is the formula for Lenses in contact?
The formula is 1/F = 1/f₁ + 1/f₂, where F = force (N), f₁ = f₁, f₂ = f₂.
What is Lenses in contact when f_1 = 7, f_2 = 5?
F = 2.916667. Substitute the values into 1/F = 1/f₁ + 1/f₂ and simplify.
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