B CompE Bachelor of Computer Engineering Digital Logic and Circuit Design 2 — Questions and Answers
Question 1: What is the hexadecimal representation of the binary number 11110000?
- E0
- F0 (Correct answer)
- 0F
- EF
Correct answer: F0
Splitting 11110000 into two nibbles: 1111 = 0xF and 0000 = 0x0, so the result is 0xF0.
Question 2: What is the purpose of a multiplexer (MUX) in digital circuits?
- Amplify digital signals
- Select one of many input signals and forward it to a single output (Correct answer)
- Convert analog to digital signals
- Store a single bit of data
Correct answer: Select one of many input signals and forward it to a single output
A multiplexer selects one of several input lines based on select signals and routes it to a single output line.
Question 3: Which Boolean theorem states that A + A = A and A AND A = A?
- Complement Law
- Idempotent Law (Correct answer)
- Absorption Law
- Distributive Law
Correct answer: Idempotent Law
The Idempotent Law states that ORing or ANDing a variable with itself returns the same variable: A+A=A and A.A=A.
Question 4: In a full adder, how many inputs does it take?
- 1
- 2
- 3 (Correct answer)
- 4
Correct answer: 3
A full adder takes three inputs: two significant bits (A and B) and a carry-in (Cin), producing a sum and carry-out.
Question 5: Which type of counter uses a sequence where only one bit changes between consecutive states?
- Binary counter
- BCD counter
- Gray code counter (Correct answer)
- Ring counter
Correct answer: Gray code counter
A Gray code counter uses the Gray code sequence where only one bit changes between consecutive values, minimizing switching errors.
Question 6: What is the two's complement of the binary number 0110?
- 1001
- 1010 (Correct answer)
- 1100
- 0110
Correct answer: 1010
Two's complement of 0110: invert all bits to get 1001 (one's complement), then add 1 to get 1010.
B CompE Bachelor of Computer Engineering Digital Logic and Circuit Design 2
What is the hexadecimal representation of the binary number 11110000?