When does the JavaScript engine assign an "Undefined" value to a variable?

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'.

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.

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 = '';

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.

What is the purpose of using 'Null' over 'Undefined' in certain programming scenarios?

A). To represent an intentional absence of value or object reference.

B). To assign default values to variables.

C). To represent uninitialized variables.

D). To check for variable existence.

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 correctly describes the purpose of 'Null' in JavaScript?

A). Null is used to represent an empty array.

B). Null is used to indicate that a variable is uninitialized.

C). Null is used to represent an intentional absence of value.

D). Null is used to check for object properties.

Which statement is true regarding the use of 'Undefined'?

A). Undefined is commonly used to reset variables in loops.

B). Undefined is generally avoided and considered a programming error.

C). Undefined is used to represent empty strings.

D). Undefined is only used in function declarations.

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.

When does a variable typically have an 'Undefined' value?

A). When it is intentionally set to represent no value.

B). When it is assigned a default value.

C). When it is declared but not initialized.

D). When it is explicitly set to 'Undefined'.