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 object
Examples :
Input : O = 50, I = 2
Output : F = 1.92308Input : O = 25, I = 5
Output : F = 4.16667
// 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;
} |
// 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 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." )
|
// 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. |
<?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. ?> |
<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 .
Time Complexity: O(1)
Auxiliary Space: O(1)