Computer Science for IGCSE & O level - Boolean Logic (Section 3)
1
Which of the following is an application of logic gates?
Answer
(D)
All of the above
2
In digital circuits, what does 'HIGH' voltage typically represent?
Answer
(B)
1
3
Which of the following best describes the operation of a NAND gate?
Answer
(A)
An AND gate followed by a NOT gate.
4
In the engine management system example, which combination of conditions would *NOT* trigger the warning light to activate?
Answer
(B)
Motor speed = 2500 rpm, bearing temperature = 85°C, water velocity = 6 m/s
5
What is the simplified expression for (A + B)' using DeMorgan's Theorem?
Answer
(B)
A' * B'
6
Which of the following statements best describes the purpose of a logic gate?
Answer
(B)
To combine one or more inputs to produce an output based on a specific rule.
7
Based on the image, which Boolean expression matches the following truth table:
| A | B | Output |
|---|---|--------|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
Answer
(C)
A XOR B
8
What is the output of the logic expression A . 1?
Answer
(C)
A
9
Which gate is used to determine the sum of two binary digits?
Answer
(C)
XOR gate
10
What is the purpose of a truth table when designing a logic circuit?
Answer
(A)
To test and confirm the intended logic of the circuit.
11
What is the relationship between the inputs and the output in a NOT gate?
Answer
(B)
The output is the inverse of the input
12
If the output of a logic gate is always 1, regardless of the input, what type of logic gate is it?
Answer
(D)
None of the above
13
If A = 1, what is the value of A'?
Answer
(A)
0
14
What operation does the OR gate perform in Boolean algebra?
Answer
(B)
Logical addition
15
What is the role of a logic expression in the context of circuit design?
Answer
(B)
To represent the circuit's operation using mathematical notation.
16
Which of the following statements is true about the XOR gate?
Answer
(C)
Output is HIGH if inputs are different
17
If the input to an AND gate are A=1 and B=0, what will be the output?
Answer
(A)
0
18
In the engine management system example, the output Y is '1' under specific conditions. If the motor speed = 3000 rpm and bearing temperature is 90°C, and water velocity is 5 m/s, what is the output?
Answer
(B)
0
19
In the engine management system, what would be the output (Y) if: Motor speed = 3000 rpm, Bearing Temperature = 75°C, Water velocity = 5 m/s?
Answer
(B)
1
20
If a circuit is meant to turn on an output when either input A or input B is true, what type of gate would most likely be utilized?
Answer
(B)
OR gate
21
What is the main advantage of using NAND gates in building logic circuits?
Answer
(B)
They can be used to construct all other basic logic gates.
22
What does the XOR gate's output represent?
Answer
(B)
The logical difference between the inputs.
23
What does the '¬' symbol represent in Boolean algebra?
Answer
(C)
NOT
24
Which gate is referred to as 'Inverter'?
Answer
(C)
NOT gate
25
What does the term 'logic level' refer to in digital electronics?
Answer
(B)
The voltage of a signal
26
Which of the following Boolean expression is equivalent to the NAND gate?
Answer
(B)
(A . B)'
27
What is the main advantage of using a truth table to assist in circuit design, based on the given examples?
Answer
(B)
It helps verify the correctness of the circuit by defining all outputs.
28
What does a NOT gate do?
Answer
(A)
Inverts the input
29
What type of operation is represented by (A AND B)'?
Answer
(A)
NAND
30
In the context of logic circuits, what is a truth table used for?
Answer
(C)
To show the outputs of a logic circuit for different input combinations.
31
What is the inverse of the AND gate?
Answer
(B)
NAND gate
32
What is the output of the logic expression: A . 0?
Answer
(A)
0
33
Which of the following options represents the NOT operation?
Answer
A
B
C
34
In the context of Boolean algebra, the OR operation can be best described as:
Answer
(B)
Only the output is 1 when any one or both inputs are 1
35
A logic circuit has three inputs: A, B, and C. The output is high (1) if and only if A and B are both high. Which logic gate would you need, along with another gate or two?
Answer
(A)
AND
36
What is the name of the gate which gives the inverted output of an OR gate?
Answer
(C)
NOR gate
37
What is the purpose of a truth table in digital logic?
Answer
(B)
To show the possible outputs of a logic gate for all possible input combinations.
38
What is the output of an AND gate if input A is 1 and input B is 0?
Answer
(A)
0
39
What is the output of a NAND gate if both inputs are 1?
Answer
(A)
0
40
How can we express NOT (A AND B) in Boolean algebra?
Answer
(C)
A' + B'
41
Which of the following logic gates is represented by the Boolean expression: Y = A + B?
Answer
(B)
OR
42
Which of the following are true about the use of NAND gates in building circuits?
Answer
A
B
C
43
How many inputs does an OR gate typically have?
Answer
(B)
2
44
Which of the following operations does an XOR gate perform?
Answer
A
D
45
Which of the following correctly describes the function of a half-adder circuit?
Answer
(B)
It adds two binary digits and produces a sum and a carry-out.
46
What type of gate inverts the input signal?
Answer
(C)
NOT
47
In the turbine example, what is the output of the system?
Answer
(C)
A binary value.
48
In the context of Boolean algebra, which operation is represented by the '+' symbol?
Answer
(B)
OR
49
In the turbine example, the value of K (the output) is determined by which condition?
Answer
(A)
Whether turbine speed is greater than 1000rpm and/or the bearing temperature is 80°C.
50
What is the relationship between the inputs and outputs of a logic circuit best described by?
