Computer Science for IGCSE & O level - Boolean Logic (Section 2)
1
Which logic gate will produce a high output if and only if all inputs are low?
Answer
(D)
NOR
2
What are the inputs to a half-adder circuit?
Answer
(A)
Two binary digits
3
How many inputs does a two-input AND gate have?
Answer
(B)
Two
4
In a logic gate, what does a 'high' signal typically represent?
Answer
(B)
1
5
What is the simplified form of (A + 0) in Boolean algebra?
Answer
(A)
A
6
What is the purpose of a carry bit in binary addition?
Answer
(A)
To indicate that an addition resulted in a sum greater than 1
7
Which of the following Boolean expressions does the logic diagram represents?
Answer
(A)
((NOT A) AND B) OR C
8
What is the sum and carry-out of a half-adder if the inputs are A=0 and B=1?
Answer
(B)
Sum=1, Carry=0
9
In the context of the examples, what is the primary benefit of using a truth table to verify a logic circuit?
Answer
(B)
It ensures that the circuit matches the logic statement.
10
In a logic circuit, the output is high (1) if motor speed is > 3000 rpm AND bearing temperature is <= 80°C, OR water velocity is > 4 m/s. Which of the following statements correctly describes the logic?
Answer
(C)
The system outputs 1 if both motor speed and bearing temperature meet the conditions, or water velocity meets the condition.
11
Which of the following is equivalent to the Boolean expression NOT (A OR B)?
Answer
(A)
NOT A AND NOT B
12
In Boolean algebra, what does the '.' symbol represent?
Answer
(B)
AND
13
Which of the following gates is the result of inverting the output of an OR gate?
Answer
(C)
NOR gate
14
Which gate is the inverse of an OR gate?
Answer
(C)
NOR gate
15
What is the purpose of a circuit diagram?
Answer
(C)
To graphically illustrate the components and their connections.
16
If the output of a logic gate is 0 only when all inputs are 1, what type of gate is it?
Answer
(B)
NOR
17
What would be the next step after writing down a logic expression from a truth table?
Answer
(A)
To create a logic circuit based on the logic expression.
18
In the context of Boolean algebra, what does '1' typically represent?
Answer
(C)
True
19
Which logic gate's output is the inverse of the output of an AND gate?
Answer
(B)
NAND gate
20
If a logic circuit's output is high (1) only when all input conditions are met, which type of gate is it?
Answer
(B)
AND gate
21
What is the output of a NOT gate if the input is 1?
Answer
(A)
0
22
What is the complement of the Boolean expression A.B?
Answer
(A)
A' + B'
23
What is the output of a 2-input AND gate if the inputs are 1 and 1?
Answer
(B)
1
24
What is the term for a number system based on two digits (0 and 1)?
Answer
(C)
Binary
25
What is the result of the expression NOT (A AND B) when A=1 and B=0?
Answer
(B)
1
26
How many inputs and outputs does a full adder have?
Answer
(C)
3 inputs, 2 outputs
27
In digital circuits, what does the term 'high' often represent?
Answer
(B)
1
28
What is the output of an OR gate if both inputs A and B are 1?
Answer
(B)
1
29
How are the three parameters related in the wood system example?
Answer
(D)
The result depends on which combination of the parameters satisfies a specific condition.
30
Which of the following statements about a NOR gate is correct?
Answer
(B)
The output is HIGH if both inputs are LOW
31
In the context of logic circuits, what is a 'high' signal typically represented by?
Answer
(C)
A binary 1
32
If all input conditions are not met, what will be the output value in many of the scenarios described?
Answer
(A)
0
33
How does the number of possible output states increase with each additional input in a logic gate?
Answer
(A)
It doubles
34
Which gate yields an output of 0 if *any* of its inputs are 1?
Answer
(D)
NOR
35
In the expression Y = (A AND B) OR C, which operation is performed LAST?
Answer
(B)
OR
36
What is the result of the Boolean expression 0 + 1?
Answer
(B)
1
37
Which of the following is the Boolean expression for a NAND gate?
Answer
(D)
(A . B)'
38
What does the term 'logic' refer to in the context of logic circuits?
Answer
(B)
The mathematical principles that govern the circuit's behavior.
39
Which of the following is the correct Boolean expression for a 2-input NOR gate?
Answer
(D)
NOT (A OR B)
40
What is the function of the logic gates?
Answer
(C)
To process binary data
41
What is the role of sensors in the logic circuit (exam-style)?
Answer
(B)
To convert real-world conditions into electrical signals for the input.
42
What is used to verify the correctness of the logic circuit?
Answer
(B)
The truth table.
43
What is the function of a 'full adder' circuit?
Answer
(A)
To add two single-bit binary numbers and a carry-in.
44
What is the most simplified form of the boolean expression: A + A'B?
Answer
(A)
A
45
The output of an AND gate is 0 if:
Answer
A
B
46
A certain logic gate always gives the output 1 if the inputs are different. Which gate is this?
Answer
(B)
XOR gate
47
What is an appropriate approach for the design of a circuit?
Answer
(A)
Start with a truth table, then create a logic expression, then draw the circuit.
48
In the logic circuit examples, what is the primary purpose of using a truth table?
Answer
(D)
To determine the output values for all possible input combinations.
49
What is the output of a NOT gate if the input is 0?
Answer
(B)
1
50
What is a truth table mainly designed to show in the examples?
Answer
(B)
All possible outputs of a logic circuit for every input combination.
