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

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

What is the scope of a variable declared with let?

A). Global

B). Function

C). Block

D). Object

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

A). SyntaxError

B). TypeError

C). ReferenceError

D). No error

Which keyword allows block-level scope in ES6?

A). var

B). let

C). function

D). var and function

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

A). let

B). var

C). const

D). static

Can const be used for objects and arrays?

A). No

B). Yes

C). Only for arrays

D). Only for objects

What happens if you try to access a let variable before its declaration?

A). Returns undefined

B). Throws a ReferenceError

C). Returns null

D). Returns an empty string

What will the following code output: { let y = 5; { let y = 10; console.log(y); } }?

A). 5

B). 10

C). undefined

D). ReferenceError

Can a variable declared with let be hoisted?

A). Yes, partially

B). No

C). Yes, fully

D). Only in strict mode

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