Which of the following is a valid use case for 'Null' in JavaScript?
A). Storing default values in variables.
B). Clearing or resetting object references.
C). Assigning placeholders in arrays.
D). Checking if a variable exists.
When does the JavaScript engine assign an 'Undefined' value to a variable?
A). When the variable is intentionally set to 'Undefined'.
B). When the variable is not declared but used.
C). When the variable is declared but not initialized.
D). When the variable is initialized with the value 'Undefined'.
What happens when a function does not explicitly return a value in JavaScript?
A). It returns 'null'.
B). It returns 'undefined'.
C). It throws an error.
D). It returns 'object'.
What is the result of the expression typeof undefinedVariable if undefinedVariable is not declared?
A). object
B). function
C). undefined
D). null
How do you check if a variable has an 'Undefined' value in JavaScript?
A). Using the undefined keyword.
B). Using the null keyword.
C). Using the typeof operator.
D). Using the empty keyword.
How does the typeof operator behave when applied to an 'Undefined' value?
A). It returns 'undefined'.
B). It returns 'null'.
C). It throws an error.
D). It returns 'object'.
Which of the following statements is correct regarding the comparison of 'Undefined' and 'Null'?
A). Undefined and Null are strictly equal in JavaScript.
B). Undefined and Null are not strictly equal in JavaScript.
C). Undefined is considered a subtype of Null.
D). Null is considered a subtype of Undefined.
How do you assign a variable to have a value of 'Null'?
A). Using the assignment operator =.
B). Using the null keyword.
C). Using the undefined keyword.
D). Using the void operator.
Which of the following is an example of using 'Null' in JavaScript?
A). let user = null;
B). let user = undefined;
C). let user;
D). let user = '';
What is the difference between 'Undefined' and 'Null' in JavaScript?
A). Undefined is a value, while Null is an absence of value.
B). Undefined is an absence of value, while Null is a value.
C). Undefined is never intentional, while Null is always intentional.
D). Undefined is always intentional, while Null is never intentional.