**Which of the following is not a positional number system?**

**a)** Roman Number System**b) **Octal Number System**c) **Binary Number System**d) **Hexadecimal Number System

**Answer: (a) Roman Number System**

**Explanation: **The Roman number system isn’t a positional number system since , it uses symbols to represent numbers. The octal number system uses digits from 0-7 , the binary number system uses digits from 0-1 whereas, the hexadecimal number system uses digits from 0-15.

2. **The value of radix in binary number system is _**

**a) **2**b)** 8**c)** 10

d) 1

**Answer: (a) 2**

**Explanation:** In a binary number system, the value of base or radix is 2. The binary system uses only two digits for the representation of numbers, therefore its base id chosen to be 2.

3. **The binary equivalent of the decimal number 10 is __**

**a)** 0010**b)** 10**c)** 1010**d)** 010

**Answer: (c) 1010**

**Explanation: **To get the binary equivalent of any number, we need to divide the number by 2 and obtain the remainders as :

We then write the remainders in the reverse order as 1010 .

4. **A computer language that is written in binary codes only is _**

**a) **machine language**b)** C**c) **C#**d)** pascal

**Answer: (a) machine language**

**Explanation:** Machine Language is written in binary codes only . It can be easily understood by the computer and is very difficult for us to understand. A machine language , unlike other languages requires no translators or interpreters

5.** The octal equivalent of 1100101.001010 is __**

**a)** 624.12**b)** 145.12**c) **154.12**d) **145.21

**Answer: (b) 145.12**

**Explanation:** The octal equivalent is obtained by grouping the numbers into three, from right to left before decimal and from right to left after the decimal place. Here,

i.e. 145.12 is the octal equivalent of the number.

6. **The input hexadecimal representation of 1110 is ___**

**a)** 0111**b)** E**c) **15**d)** 14

**Answer: (b) E**

**Explanation:** In hexadecimal number system, 1110 = 15, which is represented by the alphabet E. Some representations are:

A 10

B 11

C 12

D 13

E 14

F 15

7. **A bit in a computer terminology means either 0 or 1.**

**a) **True**b)** False.

**Answer: (a) True**

**Explanation: **A bit stands for a binary digit. A binary digit can have only two digits i.e. 0 or 1. A binary number consisting of n-bits is called a n-bit number.

8. **Convert the binary equivalent 10101 to its decimal equivalent**

**a) **21**b) **12**c)** 22**d) **31

**Answer: (a) 21**

**Explanation:** To convert a binary number to its decimal equivalent follow these steps : 24 * 1 + 23 * 0 + 22 *1 + 21 * 0 + 20 * 1 = 21. Therefore, the answer is 21.

9.** Which of the following is not a binary number?**

**a) **1111**b)** 101**c)** 11E**d)** 000

**Answer: (c) 11E**

**Explanation: **A binary number can have only two possible digits, 0 and 1. In the third option, there is an alphabet E present which makes it an invalid binary number. Alphabets are only allowed in hexadecimal number system.

10. **Which of the following is the correct representation of a binary number?**

**a)** (124)2**b)** 1110**c) **(110)2**d) **(000)2

**Answer: (d) (000)2**

**Explanation: **The binary numbers should comprise only two digits 0 and 1. Also, for the base, the value should be 2 and it should be written as a subscript enclosing the entire number. Here, the fourth option gives the correct representation