Q.1.
What will be the output of the following PHP code? 
<?php
$var=300;
$int_options = array("options"=>array ("min_range"=>0, "max_range"=>256));
if (!filter_var($var, FILTER_VALIDATE_INT, $int_options))
    echo("Integer is not valid");
else
    echo("Integer is valid");
?>

Explanation

Q.2.
Which one of the following filter checks if variable of specified type exists?
Q.3.
What will be the output of the following PHP code? 
<?php
$value = 'car';
$result = filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
?>

Explanation

Q.4.
What will be the output of the following PHP code? 
<?php
function convertSpace($string)
{
  return str_replace("_", " ", $string);
}
$string = "Peter_is_a_great_guy!";
echo filter_var($string, FILTER_CALLBACK, array("options"=>"convertSpace"));
?>

Explanation