Computer Fundamentals Multiple choice Questions and Answers on BCD for Freshers

1. A group of bits used to represent a symbol is called a ____________

a) byte
b) memory
c) nibble
d) code

Answer: a

Explanation: In binary coding, every symbol that appears in data is represented by a group of bits, which are called bytes. Computer codes use binary coding schemes.

2. BCD uses 6 bits to represent a symbol.

a) True
b) False

Answer: a

Explanation: In a Binary Coded Decimal format, 64 characters i.e. 26 different characters can be represented. It is one of the early computer codes.

3. Which of the following is not a type of computer code?

a) EBCDIC
b) BCD
c) ASCII
d) EDIC

Answer: d

Explanation: There is no coding scheme like EDIC. EBCDIC stands for Extended Binary Coded Decimal Interchange Code. BCD stands for Binary Coded Decimal. ASCII stands for American Standard Code for information interchange.

4. The BCD representation of (34)10 is _______________

a) 6
b) 7
c) 8
d) 5

Answer: b

Explanation: BCD numbers are represented as:
34 = (0011 0100)BCD.
Each digit is individually taken and an equivalent standard 4 bit term is written for the respective digit.

5. Perform BCD addition of (23)BCD + (20)BCD .

a) 00110100
b) 01000011
c) 10011
d) 11100

Answer: b

Explanation: To add any two BCD numbers :
Simply perform the addition : 23+20=43.
Then, write the equivalent BCD number = (0100 0011)BCD.

6. The weights used in Binary coded decimal code are:

a) 4,2,1
b) 8,4,2,1
c) 6,4,2,1
d) 2,1

Answer: b

Explanation: BCD is a weighted code and it uses the weights 8,4,2,1 respectively. It is often called the 8421 code. Since, it uses 4 bits for the representation therefore the weights are assigned as : 23 = 8, 22 = 4, 21 = 2, 20 = 1.

7. Write the decimal equivalent for (110001)BCD.

a) 31
b) 13
c) C1
d) 1C

Answer: a

Explanation: To obtain the decimal equivalent :
We start from the rightmost bit and make groups of 4, then write the decimal equivalent accordingly.
0011 0001 = (31)10.

8. The 9’s complement of 45 is _____________

a) 45
b) 54
c) 64
d) 46

Answer: b

Explanation: The 9’s complement of a number is obtained by subtracting each digit from 9. Here, 99-45=54. Therefore, the 9’s complement is 54.

9. The 10’s complement of 455 is _________

a) 543
b) 544
c) 545
d) 546

Answer: c

Explanation: To obtain the 10’s complement, we first obtain the 9’s complement and then add 1 to it.
999-455=544 (9’s)
544+1=545(10’s).

10. The Excess-3 representation of (0100)BCD is __________

a) 0110
b) 1110
c) 0111
d) 1100

Answer: c

Explanation: The excess-3 code is obtained by adding 3 to the BCD code.
Here, 0100+0011=0111.
Also, 4+3=7.