Test your knowledge of PHP variables with these MCQs(multiple-choice questions) and answers. Learn about variable types, superglobal variables, operators, and more in this comprehensive quiz.

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1. What is a PHP variable?

  • A special character used to denote a value
  • A container for storing values or data
  • An operator used for concatenation
  • A function used for manipulating strings

Answer: b

2. Which of the following is NOT a valid PHP variable name?

  • $my_var
  • $4myvar
  • $myVar
  • $_myvar

Answer: b

3. What is the correct syntax for assigning a value to a PHP variable?

  • $variable_name = “value”;
  • “value” = $variable_name;
  • $value = $variable_name;
  • $variable_name == “value”;

Answer: a


4. Which of the following is a PHP superglobal variable?

  • $GLOBALS
  • $my_var
  • $this
  • $super

Answer: a

5. What is the scope of a PHP variable declared inside a function?

  • Global
  • Local
  • Static
  • Session

Answer: b

6. Which of the following is NOT a valid data type for a PHP variable?

  • String
  • Integer
  • Boolean
  • Character

Answer: d

7. What is the difference between $var and $$var in PHP?

  • $var is a regular variable, while $$var is a variable variable.
  • There is no difference between $var and $$var in PHP.
  • $var is used to declare constants, while $$var is used to declare variables.
  • $var is used for global variables, while $$var is used for local variables.

Answer: a

8. Which of the following is true about PHP constants?

  • They can be redefined once they are declared.
  • They are case-sensitive by default.
  • They are defined using the $ sign before the name.
  • They are declared using the define() function.

Answer: d

9. Which of the following is true about PHP variable variables?

  • They are created by using the $ sign followed by a variable name.
  • They can only be used with strings.
  • They cannot be used as function arguments.
  • They can create an unlimited number of variables.

Answer: d

10. What is the difference between global and local variables in PHP?

  • Global variables are defined outside of functions and can be accessed from anywhere in the code, while local variables are defined inside functions and can only be accessed within that function.
  • Global variables are always arrays, while local variables can be any data type.
  • Local variables are defined outside of functions and can be accessed from anywhere in the code, while global variables are defined inside functions and can only be accessed within that function.
  • There is no difference between global and local variables in PHP.

Answer: a

11. What is the output of the following code snippet?

$var = 5;
$var2 = "10";
$result = $var + $var2;
echo $result;
  • 15
  • “15”
  • 510
  • “510”

Answer: a

12. What is the difference between == and === operators in PHP?

  • == compares two values for equality, while === also checks if the two values have the same data type.
  • == compares two values for inequality, while === checks if the two values are identical in every way.
  • == is used for assignment, while === is used for comparison.
  • == and === are interchangeable and have no difference in functionality.

Answer: a

13. What is the purpose of the unset() function in PHP?

  • To remove a variable and free up its memory
  • To delete a file from the server
  • To display an error message
  • To initialize a variable with a default value

Answer: a

14. What is the output of the following code snippet?

$var = 5;
function myFunction() {
    global $var;
    $var = 10;
}
myFunction();
echo $var;
  • 5
  • 10
  • “var”
  • “myFunction”

Answer: b

15. What is the purpose of the extract() function in PHP?

  • To import all variables from an array into the current symbol table
  • To encrypt a string
  • To decode a URL-encoded string
  • To convert a string to an array

Answer: a

16. Which of the following is not a valid PHP variable name?

  • $my_variable
  • $myVariable
  • $my variable
  • $_myVariable

Answer: c

17. What is the scope of a variable declared inside a function in PHP?

  • Global
  • Local
  • Class
  • Function

Answer: b

18. What is the difference between single and double quotes in PHP when defining a string variable?

  • Single quotes do not allow the use of escape sequences, while double quotes do.
  • Double quotes allow the use of escape sequences, while single quotes do not.
  • Single quotes allow variable substitution, while double quotes do not.
  • Double quotes allow variable substitution, while single quotes only allow it for numeric variables.

Answer: b

19. What is the purpose of the isset() function in PHP?

  • To determine if a variable is set and is not null
  • To delete a file from the server
  • To display an error message
  • To initialize a variable with a default value

Answer: a

20. What is the output of the following code snippet?

$x = 5;
$y = &$x;
$y = 10;
echo $x;
  • 5
  • 10
  • “x”
  • “y”

Answer: b

21. What is the output of the following code snippet?

$x = 5;
$y = "5";
if ($x == $y) {
    echo "Equal";
} else {
    echo "Not equal";
}
  • Equal
  • Not equal
  • Undefined variable error
  • Syntax error

Answer: a

22. Which of the following is a superglobal variable in PHP?

  • $GLOBALS
  • $SESSION
  • $POST
  • $REQUEST

Answer: a

23. What is the difference between the ‘==” and ‘===’ operators in PHP?

  • The ‘==’ operator only checks for value equality, while the ‘===’ operator checks for both value and type equality.
  • The ‘==’ operator checks for both value and type equality, while the ‘===’ operator only checks for value equality.
  • The ‘==’ operator checks if the variables are identical, while the ‘===’ operator checks if the variables are not identical.
  • The ‘==’ operator and ‘===’ operator are identical in their functionality.

Answer: a

24. What is the difference between the ‘unset()’ and ‘null’ keywords in PHP?

  • ‘unset()’ destroys a variable and frees its memory, while ‘null’ sets a variable to a null value.
  • ‘unset()’ sets a variable to a null value, while ‘null’ destroys a variable and frees its memory.
  • ‘unset()’ and ‘null’ both destroy a variable and free its memory.
  • ‘unset()’ and ‘null’ are identical in their functionality.

Answer: a

25. What is the output of the following code snippet?

$x = "10";
$y = 5;
echo $x + $y;
  • 15
  • “10+5”
  • 10
  • “15”

Answer: a

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