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