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
What does the Symbol data type represent in JavaScript?
A). A unique identifier
B). A number
C). A boolean value
D). An object
Which of the following is not a primitive value in JavaScript?
A). Number
B). Boolean
C). Object
D). String
What is the default value of a variable in JavaScript if it is not initialized?
A). null
B). undefined
C). 0
D). 'undefined'
What is the data type of the value undefined in JavaScript?
A). String
B). Object
C). Undefined
D). Number
Which symbol is used to represent a boolean value in JavaScript?
A). #
B). $
C). !
D). true/false
Which primitive value represents absence of value or no value assigned?
A). undefined
B). null
C). 0
D). 'undefined'
Which of the following statements about primitive values in JavaScript is true?
A). They are mutable
B). They are passed by reference
C). They are stored on the heap
D). They are immutable
What is a primitive value in JavaScript?
A). A complex data structure
B). A basic data type
C). A function
D). An array
What is the result of the expression 5 + '5' in JavaScript?
A). 10
B). '55'
C). '10'
D). Error