Computer Science for IGCSE & O level - Boolean Logic (Section 11)
1
In the context of binary addition, what does the 'carry' bit represent?
Απάντηση
(B)
The amount to be carried over to the next most significant bit column.
2
If you have an OR gate, and you want the output to be 0, what must the inputs be?
Απάντηση
(C)
Both 0
3
Which gate is the inverse of an OR gate?
Απάντηση
(B)
NOR
4
In a digital circuit, a NAND gate can be formed by combining an AND gate and a:
Απάντηση
(A)
NOT gate
5
In the half adder circuit, the output is a carry if both inputs are:
Απάντηση
(B)
1
6
Which of the following is true about logic gates?
Απάντηση
(B)
They are made up of thousands of transistors
7
Which of these is not a common logic gate?
Απάντηση
(D)
NOR
8
What logic gate produces an output of 1 only if its inputs are different?
Απάντηση
(C)
XOR
9
Which of the following logic gates produces a 1 output if and only if all its inputs are 0?
Απάντηση
(C)
NOR
10
When both inputs to a NAND gate are HIGH, the output is:
Απάντηση
(B)
LOW
11
What is the simplified form of the expression A OR (A AND B)?
Απάντηση
(A)
A
12
Which logic gate produces an output that is the inverse of the OR gate's output?
Απάντηση
(B)
NOR gate
13
What is the fundamental function of a logic gate in digital circuits?
Απάντηση
(B)
To perform logical operations.
14
The NAND gate is equivalent to an AND gate followed by what logic gate?
Απάντηση
(C)
NOT gate
15
Which of the following statements describes an XOR gate?
Απάντηση
(C)
Outputs HIGH if and only if inputs are different
16
A NOR gate can be made using which combination of gates?
Απάντηση
(B)
OR and NOT
17
Which is the equivalent expression for NOT (A AND B)?
Απάντηση
(B)
NOT A OR NOT B
18
What does the term 'binary value' represent?
Απάντηση
(B)
A number in base 2
19
What is the carry output in a half adder if A=1 and B=0?
Απάντηση
(A)
0
20
In a half adder circuit, what does 'sum' represent?
Απάντηση
(A)
The result of adding two input bits without considering the carry.
21
The output of a NAND gate is LOW only when:
Απάντηση
(C)
All inputs are HIGH
22
What is the output of a NAND gate if both inputs are 1?
Απάντηση
(A)
0
23
What is the output of an XNOR gate when the inputs are 1 and 1?
Απάντηση
(B)
1
24
What is the result of the Boolean expression A + A?
Απάντηση
(C)
A
25
What does a Karnaugh map (K-map) help to simplify?
Απάντηση
(A)
Logic circuits
26
Which logic gate is the complement of an OR gate?
Απάντηση
(B)
NOR
27
A logic gate's function can be completely described by:
Απάντηση
(B)
A truth table
28
In a series of logic operations represented by a truth table, what defines an input?
Απάντηση
(A)
Independent variables that affect output.
29
If A = 1, what is the result of NOT A?
Απάντηση
(A)
0
30
If the inputs to a 2-input AND gate are A=0 and B=0, what is the output?
Απάντηση
(A)
0
31
Which of the following is equivalent to the logic expression NOT(A AND B)?
Απάντηση
(C)
NOT A OR NOT B
32
What does the 'sum' output represent in a half adder?
Απάντηση
(B)
The result of the binary addition
33
What type of gate results from inverting the output of a NAND gate?
Απάντηση
(B)
OR
34
What is the output of a 2-input XOR gate if the inputs are A=1 and B=0?
Απάντηση
(B)
1
35
How many logic gates are used to build a half adder circuit?
Απάντηση
(C)
3
36
Which of the following is the simplified Boolean expression for a NAND gate with inputs A and B?
Απάντηση
(C)
(A . B)'
37
What is the output of a 2-input AND gate when A=1 and B=0?
Απάντηση
(A)
0
38
Which logic gate has an output of 1 only when both inputs are 1?
Απάντηση
(B)
AND gate
39
If the inputs of an AND gate are A = 1 and B = 0, what will be the output?
Απάντηση
(A)
0
40
Which type of gate can be described as an 'inverter'?
Απάντηση
(C)
NOT gate
41
What type of logic gate is described by the expression NOT(A OR B)?
Απάντηση
(C)
NOR gate
42
Which of the following Boolean expressions is equivalent to a NAND gate?
Απάντηση
(D)
(A * B)'
43
Which gate outputs a HIGH (1) unless both inputs are HIGH (1)?
Απάντηση
(A)
NAND
44
Which of the following gates is the most suitable for the application of a 'voting' system, where the output should be HIGH if a majority of inputs are HIGH?
Απάντηση
(B)
OR
45
What is the purpose of a decoder in digital circuits?
Απάντηση
(C)
To select one of several output lines based on the input.
46
Which one is a key advantage of using logic gates in computers?
Απάντηση
(C)
They are very reliable.
47
What is the purpose of the NOT gate in digital circuits?
Απάντηση
(B)
To invert the signal.
48
How many input combinations exist for a logic gate with two inputs?
Απάντηση
(C)
4
49
A truth table is a table that shows the output of a logic gate for every possible combination of:
Απάντηση
(B)
Inputs and outputs.
50
Which of these is the correct expression for the NOT gate?
