Computer Science for IGCSE & O level - Boolean Logic (Section 9)
1
What is the inverse of the OR gate?
Answer
(B)
NOR gate
2
A 3-input AND gate has inputs A=1, B=1, and C=0. What is the output?
Answer
(A)
0
3
What is the output of a NOR gate when all of its inputs are low?
Answer
(B)
1
4
The output of a NOR gate is HIGH (1) only when:
Answer
(B)
All inputs are LOW
5
The complement of the logical OR function is the logical ____ function.
Answer
(B)
NOR
6
What type of gate inverts the output of an OR gate?
Answer
(B)
NOR gate
7
What is the output of a NOT gate if the input is 0?
Answer
(B)
1
8
Which gate's output is HIGH (1) when either or both inputs are HIGH (1)?
Answer
(B)
OR
9
What type of gate is used to represent NOT A?
Answer
(C)
NOT gate
10
Which logic gate produces an output of 1 only when both inputs are 1?
Answer
(B)
AND
11
What logical operation does a half adder perform on two inputs?
Answer
(C)
Addition
12
In Boolean algebra, the NOT operation is also known as:
Answer
(A)
Inversion
13
Which gate produces a HIGH output when only one input is HIGH (1), but NOT both?
Answer
(C)
XOR gate
14
What is the logic function performed by a NAND gate?
Answer
(A)
AND operation followed by NOT
15
A system uses two inputs: A and B. What happens to the output of an AND gate if A=1, B=0?
Answer
(B)
Output is 0
16
Which operation does an OR gate perform?
Answer
(C)
Logical OR
17
What will be the output of an XNOR gate if A=1 and B=1?
Answer
(B)
1
18
What is the output of a 2-input NOR gate when both inputs are 1?
Answer
(A)
0
19
If the inputs to an XOR gate are A=0 and B=0, what is the output?
Answer
(A)
0
20
In a half adder, when A=0 and B=1, what is the sum?
Answer
(B)
1
21
What is the name of the table that shows the outputs of a logic gate for all possible input combinations?
Answer
(B)
A truth table
22
Which logic gate can be used to create the function of a NOT gate?
Answer
(D)
None of the above
23
Which of the following gates has a single input?
Answer
(C)
NOT gate
24
In Boolean algebra, which operator represents the 'AND' function?
Answer
(B)
*
25
Which of the following is NOT a fundamental logic gate?
Answer
(D)
XNOR
26
If the inputs of a 2-input AND gate are A=1 and B=1, the output will be?
Answer
(B)
1
27
Which of the following statements best describes an XOR gate?
Answer
(C)
Outputs HIGH when the inputs are different.
28
How many inputs does a NOT gate have?
Answer
(B)
1
29
Which logic gate's output is HIGH only if the inputs are different?
Answer
(C)
XOR
30
Which logic gate is known as the 'Inverter'?
Answer
(C)
NOT
31
What would be the output of a NOR gate with inputs A=1 and B=0?
Answer
(A)
0
32
In a complex logic circuit, what is the role of intermediate outputs?
Answer
B
D
33
What is the result when the output of an OR gate is inverted using a NOT gate?
Answer
(B)
NOR
34
Which gate produces a HIGH (1) output if both inputs are HIGH?
Answer
(C)
AND
35
Which gate is represented by the expression: (A + B)'?
Answer
(D)
NOR gate
36
When combining multiple logic gates to produce a more complex circuit, what type of gate is often placed at the end to generate the output of the circuit?
Answer
(D)
Any logic gate, depending on the expression.
37
Which of the following is the result of the Boolean expression A AND NOT B?
Answer
(C)
0 if A = 1, B = 1
38
What is the output of a 2-input XOR gate when the inputs are A = 0 and B = 1?
Answer
(B)
1
39
If the inputs to an OR gate are A=1 and B=1, what is the output?
Answer
(B)
1
40
In Boolean algebra, what does the term 'complement' mean?
Answer
(B)
The inverse or NOT operation
41
What is the purpose of a NOT gate in a digital circuit?
Answer
(B)
To invert the input signal
42
What is the output of an OR gate if the inputs are 0 and 0?
Answer
(A)
0
43
Which statement describes a logic circuit with the expression NOT (A OR B)?
Answer
(A)
It produces 1 if both A and B are 0, and 0 otherwise.
44
In Boolean algebra, what operator is used to represent the NOT operation?
Answer
(C)
!
45
How many half adders are required to create a full adder?
Answer
(B)
2
46
Which of the following gates represents the NOT gate?
Answer
(C)
The third gate
47
What is the complement of the AND gate?
Answer
(B)
NAND
48
What is the main function of the AND gate?
Answer
(A)
To output a 1 if all the inputs are 1
49
Which gate’s output is HIGH if and only if BOTH of its inputs are LOW?
Answer
(D)
NOR gate
50
What is the output state of a NAND gate if the inputs are A=1 and B=1?
