Exam 01: Introduction to Computing and Computer Systems

Exam 03: Boolean Logic and Logic Gates
Computer Science Exam Series | Time: 2 hours | Total: 84 marks

Answer all questions. Part A has 50 multiple choice questions (1 mark each). Part B has 8 short
answer questions (3 marks each). Part C has 2 longer questions (5 marks each). In Part A the
correct option is marked with a double tick. In expressions, A.B means A AND B, A+B means A OR
B and A' means NOT A. Answer key and model answers are at the end.


Part A: Multiple Choice (50 marks)
Q1. An AND gate outputs 1 when:
a) Any input is 1
b) All inputs are 1 ✔✔
c) All inputs are 0
d) Exactly one input is 1

Q2. An OR gate outputs 1 when:
a) All inputs are 1
b) At least one input is 1 ✔✔
c) All inputs are 0
d) Inputs are different

Q3. What is the output of a NOT gate when the input is 1?
a) 1
b) 0 ✔✔
c) 2
d) Undefined

Q4. What is the output of a NAND gate with both inputs equal to 1?
a) 1
b) 0 ✔✔
c) 2
d) Undefined

Q5. What is the output of a NOR gate with both inputs equal to 0?
a) 0
b) 1 ✔✔
c) 2
d) Undefined




Exam 03: Boolean Logic and Logic Gates Page 1

, Q6. What is the output of an XOR gate for inputs 1 and 0?
a) 0
b) 1 ✔✔
c) 2
d) Undefined

Q7. What is the output of an XOR gate for inputs 1 and 1?
a) 1
b) 0 ✔✔
c) 2
d) Undefined

Q8. What is the output of an XNOR gate for inputs 1 and 1?
a) 0
b) 1 ✔✔
c) 2
d) Undefined

Q9. How many rows does the truth table of a circuit with 3 inputs have?
a) 3
b) 6
c) 8 ✔✔
d) 9

Q10. How many rows does the truth table of a circuit with 4 inputs have?
a) 8
b) 12
c) 16 ✔✔
d) 4

Q11. What is A.0?
a) A
b) 0 ✔✔
c) 1
d) A'

Q12. What is A+1?
a) A
b) 0
c) A'
d) 1 ✔✔




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