What is the primary difference between var and let?

Which keyword is used to declare a read-only named constant?

A). let

B). var

C). const

D). static

What will be the output of the following code: let x = 10; { let x = 20; } console.log(x);?

A). 10

B). 20

C). undefined

D). ReferenceError

What error will the following code produce: const PI; PI = 3.14;?

A). SyntaxError

B). TypeError

C). ReferenceError

D). No error

What is the scope of a variable declared with let?

A). Global

B). Function

C). Block

D). Object

Can a let variable be redeclared in the same scope?

A). Yes

B). No

C). Only if it is a string

D). Only if it is a number

Are variables declared with let and const accessible before they are declared?

A). Yes

B). No

C). Only in strict mode

D). Only if they are numbers

Can a variable declared with let be hoisted?

A). Yes, partially

B). No

C). Yes, fully

D). Only in strict mode

Can const variables be reassigned in nested scopes?

A). Yes

B). No

C). Only if they are strings

D). Only in strict mode

What will the following code output: { const a = 10; a = 20; }?

A). 10

B). 20

C). undefined

D). TypeError

What is the temporal dead zone in ES6?

A). Time between function calls

B). Period between variable declaration and initialization

C). Time between two loops

D). Interval between event listeners