Computer Science for IGCSE & O level - Boolean Logic (Section 3)
1
Which of the following is an application of logic gates?
Απάντηση
(D)
All of the above
2
In digital circuits, what does 'HIGH' voltage typically represent?
Απάντηση
(B)
1
3
Which of the following best describes the operation of a NAND gate?
Απάντηση
(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?
Απάντηση
(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?
Απάντηση
(B)
A' * B'
6
Which of the following statements best describes the purpose of a logic gate?
Απάντηση
(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 |
Απάντηση
(C)
A XOR B
8
What is the output of the logic expression A . 1?
Απάντηση
(C)
A
9
Which gate is used to determine the sum of two binary digits?
Απάντηση
(C)
XOR gate
10
What is the purpose of a truth table when designing a logic circuit?
Απάντηση
(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?
Απάντηση
(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?
Απάντηση
(D)
None of the above
13
If A = 1, what is the value of A'?
Απάντηση
(A)
0
14
What operation does the OR gate perform in Boolean algebra?
Απάντηση
(B)
Logical addition
15
What is the role of a logic expression in the context of circuit design?
Απάντηση
(B)
To represent the circuit's operation using mathematical notation.
16
Which of the following statements is true about the XOR gate?
Απάντηση
(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?
Απάντηση
(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?
Απάντηση
(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?
Απάντηση
(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?
Απάντηση
(B)
OR gate
21
What is the main advantage of using NAND gates in building logic circuits?
Απάντηση
(B)
They can be used to construct all other basic logic gates.
22
What does the XOR gate's output represent?
Απάντηση
(B)
The logical difference between the inputs.
23
What does the '¬' symbol represent in Boolean algebra?
Απάντηση
(C)
NOT
24
Which gate is referred to as 'Inverter'?
Απάντηση
(C)
NOT gate
25
What does the term 'logic level' refer to in digital electronics?
Απάντηση
(B)
The voltage of a signal
26
Which of the following Boolean expression is equivalent to the NAND gate?
Απάντηση
(B)
(A . B)'
27
What is the main advantage of using a truth table to assist in circuit design, based on the given examples?
Απάντηση
(B)
It helps verify the correctness of the circuit by defining all outputs.
28
What does a NOT gate do?
Απάντηση
(A)
Inverts the input
29
What type of operation is represented by (A AND B)'?
Απάντηση
(A)
NAND
30
In the context of logic circuits, what is a truth table used for?
Απάντηση
(C)
To show the outputs of a logic circuit for different input combinations.
31
What is the inverse of the AND gate?
Απάντηση
(B)
NAND gate
32
What is the output of the logic expression: A . 0?
Απάντηση
(A)
0
33
Which of the following options represents the NOT operation?
Απάντηση
A
B
C
34
In the context of Boolean algebra, the OR operation can be best described as:
Απάντηση
(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?
Απάντηση
(A)
AND
36
What is the name of the gate which gives the inverted output of an OR gate?
Απάντηση
(C)
NOR gate
37
What is the purpose of a truth table in digital logic?
Απάντηση
(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?
Απάντηση
(A)
0
39
What is the output of a NAND gate if both inputs are 1?
Απάντηση
(A)
0
40
How can we express NOT (A AND B) in Boolean algebra?
Απάντηση
(C)
A' + B'
41
Which of the following logic gates is represented by the Boolean expression: Y = A + B?
Απάντηση
(B)
OR
42
Which of the following are true about the use of NAND gates in building circuits?
Απάντηση
A
B
C
43
How many inputs does an OR gate typically have?
Απάντηση
(B)
2
44
Which of the following operations does an XOR gate perform?
Απάντηση
A
D
45
Which of the following correctly describes the function of a half-adder circuit?
Απάντηση
(B)
It adds two binary digits and produces a sum and a carry-out.
46
What type of gate inverts the input signal?
Απάντηση
(C)
NOT
47
In the turbine example, what is the output of the system?
Απάντηση
(C)
A binary value.
48
In the context of Boolean algebra, which operation is represented by the '+' symbol?
Απάντηση
(B)
OR
49
In the turbine example, the value of K (the output) is determined by which condition?
Απάντηση
(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?
