Power of a lens

Write a program to determine the power of a lens . 
Power of a lens is its ability to bend light . For a convex lens, the converging ability is defined by power and in a concave lens, the diverging ability . The diopter ( D ) is the unit of measuring power of a lens . 
The power is defined as the reciprocal of the focal length in meters .
D = ( 1 / F ) 
Here, D is the power in diopter, 
F is the focal length in meters.

Examples: 

Input : F = 2
Output : D = 0.5

Input : F = 0.2
Output : D = 5

C++

// C++ program to determine
// the power of a lens
#include <iostream>
using namespace std;

// function to determine the
// power of a lens
float power(float focal_length)
{
    return (1 / focal_length);
}

// driver function
int main()
{
    float focal_length = 2;
    cout << "The power of the lens in diopter is "
         << power(focal_length);

    return 0;
}

Java

// Java program to determine
// the power of a lens
import java.io.*;

class GFG
{
    // function to determine the
    // power of a lens
    static float power(float focal_length)
    {
        return (1 / focal_length);
    }

    // Driver code
    public static void main (String[] args)
    {
        float focal_length = 2;
        System.out.println("The power of the lens in diopter is "
                           + power(focal_length));

    }
}

// This code is contributed by Gitanjali.

Python3

# Python3 program to determine
# the power of a lens

# function to determine
# the power of a lens
def power( focal_length ) :

    return ( 1 / focal_length )

# driver function
focal_length = 2 ;
print ( "The power of the lens in diopter is ", end = "")
print (power(focal_length) )

C#

// C# program to determine
// the power of a lens
using System;

class GFG
{
    // function to determine the
    // power of a lens
    static float power(float focal_length)
    {
        return (1 / focal_length);
    }

    // Driver code
    public static void Main ()
    {
        float focal_length = 2;
        Console.WriteLine("The power of the lens in diopter is "
                        + power(focal_length));

    }
}

// This code is contributed by vt_m.

PHP

<?php
// PHP program to determine
// the power of a lens

// function to determine the
// power of a lens
function power($focal_length)
{
    return (1 / $focal_length);
}

    // Driver Code
    $focal_length = 2;
    echo "The power of the lens in diopter is "
        , power($focal_length);

// This code is contributed by anuj_67.
?>

Javascript

<script>

// Javascript program to determine
// the power of a lens


// function to determine the
// power of a lens
function power( focal_length)
{
    return (1 / focal_length);
}
    // Driver Code

    let focal_length = 2;
    document.write("The power of the lens in diopter is "
        + power(focal_length));


</script>

Output

The power of the lens in diopter is 0.5

Time Complexity: O(1)
Auxiliary Space: O(1)

Source:
http://www.bbc.co.uk/bitesize/intermediate2/physics/waves_and_optics/power_of_lens/revision/1/