Program for focal length of a lens

Write a program to determine the focal length of a lens.

Focal length is the distance between the center of the lens to the principal foci. In order to determine the focal length of a lens we should know the distance between the lens and the image ( I ) and the distance between the lens and the object ( O ). Here, we will use the lens equation also called the focal length equation.

The lens equation is :



 \frac{1} {F}  = \frac {1}{O}  +  \frac{1}{I} 

here,
F is the focal length
I is the distance between the lens and the image
O is the distance between the lens and the object

Examples :

Input : O = 50, I = 2
Output : F = 1.92308

Input : O = 25, I = 5
Output : F = 4.16667

C++

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// C++ program to determine
// the focal length of a lens
#include <iostream>
using namespace std;
  
// Function to determine the focal length of a lens
float focal_length(float image_distance, float object_distance)
{
    return 1 / ((1 / image_distance) + (1 / object_distance));
}
  
// Driver function
int main()
{
    // variable to store the distance
    // between the lens and the image
    float image_distance = 2;
  
    // variable to store the distance
    // between the lens and the object
    float object_distance = 50;
  
    cout << "Focal length of a lens is "
         << focal_length(image_distance, object_distance)
         << " units .";
  
    return 0;
}

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Java

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// Java program to determine
// the focal length of a lens
  
import java.io.*;
  
class GFG {
  
    // Function to determine the focal
    // length of a lens
    static float focal_length(float image_distance,
                              float object_distance)
    {
        return 1 / ((1 / image_distance) + 
                           (1 / object_distance));
    }
  
    public static void main(String[] args)
    {
  
        // variable to store the distance
        // between the lens and the image
        float image_distance = 2;
  
        // variable to store the distance
        // between the lens and the object
        float object_distance = 50;
          
        System.out.println("Focal length of a lens is "
        + focal_length(image_distance, object_distance)
                                         + " units.");
    }
}
  
// This code is contributed by Ajit.

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Python3

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# Python3 program to determine
# the focal length of a lens
  
# Function to determine the focal length of a lens
def focal_length(image_distance, object_distance)
    : return 1 / ((1 / image_distance) + (1 / object_distance))
  
# Driver Code
# Variable to store the distance
# between the lens and the image
image_distance = 2
  
# Variable to store the distance
# between the lens and the object
object_distance = 50
  
result = focal_length(image_distance, object_distance)
print("Focal length of a lens is ", result, " units.")

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C#

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// C# program to determine
// the focal length of a lens
using System;
  
class GFG {
  
    // Function to determine the focal
    // length of a lens
    static float focal_length(float image_distance,
                            float object_distance)
    {
        return 1 / ((1 / image_distance) + 
                    (1 / object_distance));
    }
      
    // Driver code
    public static void Main()
    {
  
        // variable to store the distance
        // between the lens and the image
        float image_distance = 2;
  
        // variable to store the distance
        // between the lens and the object
        float object_distance = 50;
          
        Console.WriteLine("Focal length of a lens is "
        + focal_length(image_distance, object_distance)
                                        + " units.");
    }
}
  
// This code is contributed by Vt_m.

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PHP

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<?php
// PHP program to determine
// the focal length of a lens
// Function to determine the 
// focal length of a lens
function focal_length($image_distance
                      $object_distance)
{
    return 1 / ((1 / $image_distance) + 
               (1 / $object_distance));
}
  
    // Driver Code
      
    // variable to store the distance
    // between the lens and the image
    $image_distance = 2;
  
    // variable to store the distance
    // between the lens and the object
    $object_distance = 50;
  
    echo "Focal length of a lens is "
        , focal_length($image_distance
                      $object_distance)
        , " units .";
  
// This code is contributed by anuj_67.
?>

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Output :

Focal length of a lens is 1.92308 units . 


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Improved By : vt_m



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