What will be the output of the following code?
const a = 10; a = 20; console.log(a);
A). 10
B). 20
C). Error
D). undefined
Which of the following is NOT a valid variable name in JavaScript?
A). myVar
B). $myVar
C). _myVar
D). 123myVar
Which statement is true about variables in JavaScript?
A). They must be declared before use
B). They can only hold numbers
C). They are statically typed
D). They are strongly typed
What will be the output of the following code?
console.log(a); var a = 10;
A). 10
B). undefined
C). Error
D). null
What will be the output of the following code?
var x = 5; var y = 6; var z = x + y;
A). 11
B). 11
C). 5
D). 6
Can variables declared with 'var' be redeclared in the same scope?
A). Yes
B). No
C). Only inside a function
D). Only inside a loop
What is the difference between let and var?
A). let is function-scoped, var is block-scoped
B). let is block-scoped, var is function-scoped
C). Both are block-scoped
D). Both are function-scoped
Which of the following will cause an error?
A). let a = 10; a = 20;
B). const a = 10; a = 20;
C). var a = 10; a = 20;
D). None of the above
What is the correct syntax for declaring a variable in JavaScript?
A). let myVar = 5;
B). myVar let = 5;
C). 5 = let myVar;
D). let = myVar 5;
Which of the following is true about 'const' variables in JavaScript?
A). They can be redeclared
B). They cannot be reassigned
C). They can be reassigned
D). They are always undefined