1. The Excess-3 code is derived by adding what value to the decimal digit?

A. 1 B. 2 C. 3 D. 4

2. How do you detect overflow in 8-bit 2’s complement addition?

A. Check if the carry into and out of the MSB differ B. Count the number of 1’s in the sum C. Check if sum is zero D. Check if the sum is greater than 255

3. What is a nibble in digital systems?

A. 2 bits B. 4 bits C. 8 bits D. 16 bits

4. Why are octal and hexadecimal convenient for representing binary numbers?

A. Because they use fewer symbols than binary B. Because they correspond to groups of three and four binary digits respectively C. Because they do not require place values D. Because they are non-positional systems

5. Which of the following is true about positional number systems?

A. The value of a digit depends on its position in the number B. Each digit has the same value regardless of position C. Positions are not relevant D. Digits are only 0 or 1

6. What is the purpose of 2’s complement in signed binary numbers?

A. To simplify subtraction by converting it to addition B. To represent only positive numbers C. To encode decimal fractions D. To detect parity errors

7. When performing binary addition of two 8-bit signed numbers, what indicates an overflow?

A. When the carry out from the most significant bit is zero B. When the result is negative regardless of inputs C. When the carry into and out of the most significant bit differ D. When all bits are zero

8. What binary number corresponds to the Gray code 0110?

A. 0101 B. 0010 C. 0111 D. 0100

9. What is the BCD code for decimal number 59?

A. 0101 1001 B. 0101 1010 C. 1001 0101 D. 0011 1001

10. What is the primary use of BCD coding?

A. Data compression B. Representing decimal digits in binary form C. Error detection D. Encryption

11. Which of the following is the place value of the third position from the right in binary numbering?

A. \(2^2\) B. \(2^3\) C. \(2^1\) D. \(2^0\)

12. Which number system is non-positional?

A. Binary B. Octal C. Roman numerals D. Hexadecimal

13. Which of these best explains the term ‘word’ in digital systems?

A. A group of 4 bits B. A predefined number of bits processed as a unit, typically more than 8 bits C. A single bit representing information D. Two bytes combined

14. Which of these codes is used specifically to reduce errors in rotary encoders?

A. ASCII B. BCD C. Gray code D. Excess-3

15. What is the octal equivalent of binary number 110101011?

A. 653 B. 665 C. 153 D. 333

16. What is the binary equivalent of decimal 156?

A. 10011100 B. 10011010 C. 10011101 D. 10011011

17. The place values for the hexadecimal system start with \(16^0\). What is the place value at the 5th position from the right?

A. \(16^3\) B. \(16^4\) C. \(16^5\) D. \(16^2\)

18. What is the primary advantage of hexadecimal over binary?

A. Uses fewer digits to represent the same value B. Easier to perform addition C. Only uses digits 0 and 1 D. There is no advantage

19. What is the result of subtracting (1101)2 from (100000)2?

A. 111011 B. 101011 C. 011011 D. 010011

20. Which of the following is a correct 8-bit 2’s complement representation for -25?

A. 00011001 B. 11100111 C. 11100111 D. 11100111

21. Convert decimal 92 to Excess-3 code.

A. 1100 0101 B. 1101 0010 C. 1100 0101 D. 1011 1101

22. What is the sum of the binary numbers (10101111)2 and (01110101)2?

A. 100100100 B. 00100100 C. 11011100 D. 10100010

23. Which of the following is a positional number system?

A. Roman numerals B. Binary system C. Morse code D. Tally marks

24. Convert decimal 92 to BCD.

A. 1001 0010 B. 1001 0100 C. 0100 1010 D. 0110 0001

25. What is the Excess-3 code for the decimal digit 7?

A. 1010 B. 1011 C. 1100 D. 1011

26. What correction is necessary in BCD addition when the sum of two digits exceeds 9?

A. Subtract 6 B. Add 6 C. Subtract 3 D. Add 3

27. Which of the following is the 7-bit ASCII representation for uppercase letter ‘A’?

A. 1000001 B. 1100001 C. 1010001 D. 1000010

28. What is the result of adding two BCD numbers 39 and 27 with correction?

A. 0110 0110 B. 0010 0110 C. 0110 0100 D. 0110 1000

29. What is the 8421 BCD code for decimal 307?

A. 0011 0000 0111 B. 0011 0001 0110 C. 0001 0111 0011 D. 0010 0110 0111

30. What is the binary representation of the hexadecimal number \(3AF\)?

A. 0011 1010 1111 B. 0011 1110 1110 C. 0011 1011 1110 D. 0010 1010 1111

31. Which number system uses digits 0 to 7?

A. Binary B. Octal C. Decimal D. Hexadecimal

32. Which operation is performed by the binary subtraction \(14 - 27\) using 2’s complement?

A. Addition of 14 and 27 B. Addition of 14 and -27 C. Subtraction of 27 from 14 directly D. Complement of \(14+27\)

33. Which of the following is true about signed 8-bit 2’s complement number range?

A. 0 to 255 B. -128 to 127 C. -127 to 128 D. 0 to 127

34. In ASCII, which 7-bit binary corresponds to the digit ‘9’?

A. 01111001 B. 00111001 C. 00110001 D. 01111000

35. What is the main advantage of Gray code in mechanical or rotary encoders?

A. It increases the number of detectable errors B. It reduces switching errors by only one bit changing between successive codes C. It uses fewer bits per code D. It is easier to convert to decimal numbers

36. Which of these codes is an example of a weighted binary code?

A. Gray code B. BCD (8421) C. Excess-3 D. ASCII

37. How is the ASCII character ‘A’ represented in 7-bit binary code?

A. 1000001 B. 1111111 C. 0100001 D. 1100000

38. Which of the following is true about the binary to Gray code conversion?

A. The first Gray code digit is the same as the binary digit’s least significant bit B. Every Gray code digit is the XOR of the corresponding binary digit and the previous binary digit C. Gray code digits are obtained by counting the number of ones in the binary number D. They are identical for all even numbers

39. What is the Gray code equivalent of the binary number 101011?

A. 111011 B. 111010 C. 101011 D. 100011

40. How is the ASCII character ‘CAT’ represented as a binary stream?

A. 01000011 01000001 01010100 B. 01000010 01000001 01010100 C. 01000011 01000010 01010100 D. 01000011 01000001 01010010

41. In 8-bit 2’s complement representation, which of the following correctly represents -45?

A. 11010011 B. 00101101 C. 11101011 D. 10110011

42. Which is a characteristic feature of Gray code?

A. Only one bit changes between successive numbers B. Only even numbers are represented C. It is a weighted code D. It is used only in computers

43. Does overflow occur when adding (10101111)2 and (01110101)2 in 8-bit signed representation?

A. Yes B. No C. Sometimes D. Cannot be determined

44. Which of the following best defines Excess-3 code?

A. A decimal code in which each digit is represented by adding 3 to its binary equivalent B. A binary code used to represent alphabets only C. A coding system where each bit represents a power of two D. A sequence of bits used in error detection

45. What does ASCII stand for?

A. American Standard Code for Information Interchange B. Automated System Code for Intelligent Interchange C. American Standard Codex for Internal Instructions D. Automated Sequence Code for Interchange

46. What is the radix (base) of the hexadecimal number system?

A. 2 B. 8 C. 10 D. 16

47. What is the 2’s complement of the 8-bit binary number 00110110?

A. 11001010 B. 11001011 C. 11001101 D. 11001010

48. What is the binary equivalent of the hexadecimal number 3B7?

A. 0011 1011 0111 B. 0011 1101 0111 C. 1001 0110 1110 D. 0110 1011 1110

49. What does the radix or base of a number system represent?

A. The total number of digits used in the system B. The value of the highest digit in the system C. The number of unique digits including zero used to represent numbers D. The position of the decimal point

50. How many bits are there in one nibble?

A. 4 B. 8 C. 16 D. 32