**Answers to the above questions Related: Real Numbers - MCQ with Solution, Class 10 Mathematics**

**1. Which of the following is not a rational number?**
The correct answer is (c) √3.

**Explanation:**
Rational numbers are those numbers that can be expressed as a fraction of two integers, where the denominator is not equal to zero. The square root of 3 (√3) is an irrational number because it cannot be expressed as a fraction. Irrational numbers cannot be expressed as terminating or repeating decimals. Therefore, √3 is not a rational number.

**2. Which of the following is a rational number?**
The correct answer is (b) 0.6666...

**Explanation:**
A rational number is a number that can be expressed as a fraction of two integers. The number 0.6666... can be expressed as the fraction 2/3. When we divide 2 by 3, we get 0.6666... as the decimal representation. Therefore, 0.6666... is a rational number.

**3. Which of the following is not a real number?**
The correct answer is (d) i^2.

**Explanation:**
Real numbers include all rational and irrational numbers. The square of the imaginary unit (i^2) is equal to -1, which is a real number. Therefore, i^2 is a real number and not excluded from the set of real numbers.

**4. Which of the following is a real number?**
The correct answer is (a) 5.

**Explanation:**
Real numbers include both rational and irrational numbers. The number 5 is a rational number, as it can be expressed as a fraction 5/1. Since 5 is a rational number, it is also a real number.

**5. Which of the following is an irrational number?**
The correct answer is (c) √2.

**Explanation:**
An irrational number is a number that cannot be expressed as a fraction of two integers. The square root of 2 (√2) is an irrational number because it cannot be expressed as a fraction. It is a non-repeating and non-terminating decimal. Therefore, √2 is an irrational number.

Ans are as following respectively, c , b,b,c,d,a,c,a,d,d,b,b,d,c( except Q11) if you have any problem them you can ask