Program for focal length of a lens

12 Apr, 2021
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 :  
 =  + 
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 objectExamples :  
Input : O = 50, I = 2
Output : F = 1.92308

Input : O = 25, I = 5
Output : F = 4.16667
 
 
C++
Java
Python3
C#
PHP
Javascript
// C++ program to determine// the focal length of a lens#include <iostream>using namespace std; // Function to determine the focal length of a lensfloat focal_length(float image_distance, float object_distance){    return 1 / ((1 / image_distance) + (1 / object_distance));} // Driver functionint 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;}
// 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.
# Python3 program to determine# the focal length of a lens # Function to determine the focal length of a lensdef 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 imageimage_distance = 2 # Variable to store the distance# between the lens and the objectobject_distance = 50 result = focal_length(image_distance, object_distance)print("Focal length of a lens is ", result, " units.")
// C# program to determine// the focal length of a lensusing 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.
<?php// PHP program to determine// the focal length of a lens// Function to determine the// focal length of a lensfunction 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.?>
<script> // javascript 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 Function          // variable to store the distance        // between the lens and the image        let image_distance = 2;           // variable to store the distance        // between the lens and the object        let object_distance = 50;                   document.write("Focal length of a lens is "        + focal_length(image_distance, object_distance)                                         + " units.");            </script>
Output : 
Focal length of a lens is 1.92308 units . 
 
vt_m
souravghosh0416
Mathematical
School Programming
Mathematical
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