Q
What is the result of the expression undefined + null in JavaScript?

Answer & Solution

Answer: Option C
Solution:
JavaScript performs implicit type conversion, treating undefined as NaN and null as 0 when adding them.
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What is the default value of a variable in JavaScript if it is not initialized?

A). null

B). undefined

C). 0

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Which of the following is a valid way to represent the value null in JavaScript?

A). undefined

B). NULL

C). null

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What is the result of the expression true + false in JavaScript?

A). true

B). false

C). 1

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A). SyntaxError is thrown

B). ReferenceError is thrown

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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

What is the data type of the value NaN in JavaScript?

A). Number

B). String

C). Object

D). Undefined

Which symbol is used to represent a boolean value in JavaScript?

A). #

B). $

C). !

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Which of the following statements is true about primitive data types in JavaScript?

A). They have methods and properties

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What happens when you add two numbers using the + operator in JavaScript?

A). The numbers are concatenated

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D). An error occurs

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A). undefined

B). null

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