**Question 1:** Difference Between "null" and "undefined" data type with example?

**Question 2:** What type of variable should you **initialize** at the time of declaration?

**Question 3:** Guess the **Output** and Explain Why?

let languages = "java javaScript python cSharp";

let result = languages.lastIndexOf("S");

console.log(result)

**Question 4:** Guess the **Output** and Explain Why?

let variable = "hello programmers";

let result = Number(variable);

console.log(result);

**Question 5:** Guess the **Output** and Explain Why?

let num1 = 32;

let num2 = "32";

let result1 = num1 !== num2;

let result2 = num1 != num2;

console.log(result1,result2);

**Question 6:** Guess the **Output** and explain Why?

let str = "Hello Programmers";

let result = str.includes("r");

console.log(result);

**Question 7:** Guess the **Output** and Explain Why?

let num1 = 2;

let num2 = 5;

let result = num1**num2*2;

console.log(result);

**Question 8:** Guess the **Output** and Explain Why?

let num1 = [1,2,4,5];

let num2 = [6,5,8,0];

let result = num1.concat(num2);

console.log(result)

**Question 9:** Guess the **Output** and Explain Why?

let a = 5;

let b = 7;

let c = 8;

let result = a<b>c;

console.log(result)