What does the Symbol data type represent in JavaScript?
A). A unique identifier
B). A number
C). A boolean value
D). An object
What is the result of the expression undefined + null in JavaScript?
A). undefined
B). null
C). 0
D). Error
What is the data type of the value NaN in JavaScript?
A). Number
B). String
C). Object
D). Undefined
What is the result of the expression true + false in JavaScript?
A). true
B). false
C). 1
D). 0
What happens when you try to access a variable that has not been declared in JavaScript?
A). SyntaxError is thrown
B). ReferenceError is thrown
C). TypeError is thrown
D). Undefined
Which of the following statements is true about primitive data types in JavaScript?
A). They have methods and properties
B). They can be used as keys in objects
C). They are instances of Object
D). They are passed by value
Which of the following is a valid JavaScript symbol?
A). symbol
B). &symbol
C). #symbol
D). Symbol('description')
Which primitive value represents absence of value or no value assigned?
A). undefined
B). null
C). 0
D). 'undefined'
What is the data type of the value undefined in JavaScript?
A). String
B). Object
C). Undefined
D). Number
What is the default value of a variable in JavaScript if it is not initialized?
A). null
B). undefined
C). 0
D). 'undefined'