Redeclaring Variables Mockest | JavaScript

11.

Which of the following is a characteristic of 'const' variables?

A). They can be redeclared B). They can be reassigned C). They cannot be redeclared but can be reassigned D). They cannot be redeclared or reassigned

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12.

How does the scope of 'var' differ from 'let' and 'const' inside a function?

A). 'var' is block-scoped, 'let' and 'const' are function-scoped B). 'var', 'let', and 'const' are all block-scoped C). 'var' is function-scoped, 'let' and 'const' are block-scoped D). 'var' and 'let' are block-scoped, 'const' is function-scoped

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13.

What error is thrown when attempting to redeclare a 'const' variable?

A). TypeError B). ReferenceError C). SyntaxError D). RangeError

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14.

Which of the following correctly describes variable hoisting with 'let' and 'const'?

A). Both 'let' and 'const' declarations are not hoisted B). Only 'let' declarations are hoisted C). Only 'const' declarations are hoisted D). Both 'let' and 'const' declarations are hoisted but not initialized

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15.

What will happen if you declare a 'let' variable inside a block and try to access it outside the block?

A). It will return undefined B). It will throw a ReferenceError C). It will return null D). It will be accessible outside the block

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16.

Can you redeclare a 'var' variable in a different scope without error?

A). Yes B). No C). Only in strict mode D). Only if the variable is not initialized

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17.

What happens when you redeclare a variable with 'var' inside a function?

A). The variable is overwritten B). The variable declaration is ignored C). It throws an error D). The function's scope is reset

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18.

Why is it recommended to use 'let' and 'const' over 'var' in modern JavaScript?

A). 'let' and 'const' are function-scoped B). 'let' and 'const' prevent variable hoisting C). 'let' and 'const' are block-scoped, reducing potential errors D). 'let' and 'const' are faster

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19.

Which of the following statements about 'let' and 'const' is false?

A). Both 'let' and 'const' are block-scoped B). Both 'let' and 'const' cannot be redeclared in the same scope C). 'let' can be reassigned, 'const' cannot D). Both 'let' and 'const' can be redeclared in different scopes

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20.

What will happen if you try to use a variable before declaring it with 'let'?

A). It will return undefined B). It will return null C). It will throw a ReferenceError D). It will return NaN

Answer & Solution Discuss in Board

Redeclaring Variables Mocktest

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