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

Can const be used for objects and arrays?

A). No

B). Yes

C). Only for arrays

D). Only for objects

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

A). 10

B). 20

C). undefined

D). TypeError

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

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

A). 5

B). 10

C). undefined

D). ReferenceError

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 is the value of a const variable once it is assigned?

A). Can be changed later

B). Cannot be changed later

C). Depends on the data type

D). Undefined initially

What is the primary difference between var and let?

A). Scope

B). Initialization

C). Data type

D). Assignment

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

A). SyntaxError

B). TypeError

C). ReferenceError

D). No error