| Date | May 2021 | Marks available | 2 | Reference code | 21M.1.SL.TZ0.3 |
| Level | SL | Paper | 1 | Time zone | no time zone |
| Command term | Draw | Question number | 3 | Adapted from | N/A |
Question
Draw the logic circuit represented by the following truth table.
Markscheme
Award [2 max]
Note: There could be many answers that are correct.
Example 1
Correct inputs and XOR gate;
NOT gate, correct final output and link from XOR gate;
Example 2
Award [2] max.
2 marks, 1 mark for each correct input in OR gate
Note: in this example the two inputs in OR gate are (NOT A AND NOT B )and (A AND B).
1 mark for drawing any 3 gates (complete with inputs and outputs)
Examiners report
A wide range of correct logic circuits were seen in answer to this question, including logic gates from the syllabus – the XOR and NOT gates, as well as above level responses, including the XNOR gate. Some candidates incorrectly used regular OR or NOR gates in their solutions.
Syllabus sections
-
18M.1.SL.TZ0.3:
Calculate how many different colours can be represented using two hexadecimal characters.
-
21N.1.HL.TZ0.2:
State the hexadecimal representation of the binary number 10001010.
-
22M.1.SL.TZ0.8:
Identify one function of a single-user operating system.
-
22M.1.SL.TZ0.6:
Draw the truth table for the following logic circuit.
-
22M.1.SL.TZ0.7a:
Calculate, showing your working in each case: the binary (base 2) value of the denary (base 10) number: 105.
-
22M.1.SL.TZ0.9:
Define the term usability.
-
22M.1.SL.TZ0.11:
Explain how cache memory affects system performance.
-
22M.1.SL.TZ0.7b:
Calculate, showing your working in each case: the hexadecimal (base 16) value of the denary (base 10) number: 200.
-
17N.1.SL.TZ0.5:
Copy and complete the following truth table.
- 17N.1.SL.TZ0.8a: State where all instructions and data are stored.
-
17N.1.SL.TZ0.11b:
State one advantage of this feature.
-
19M.1.SL.TZ0.15c:
Identify two types of general application software that would be installed on the training computers.
-
18N.1.SL.TZ0.4:
Construct a logic diagram for the following expression.
NOT A OR (A AND B)
-
18N.1.SL.TZ0.8c.i:
State how the data stored in the byte will be represented in hexadecimal.
- 19M.1.SL.TZ0.5: State the hexadecimal equivalent of the following binary number: 11011111
-
19M.1.SL.TZ0.6:
Construct the truth table from the following logic circuit.
-
18M.1.SL.TZ0.2:
Outline the role of the memory data register in the machine execution cycle.
-
17N.1.HL.TZ0.10a:
Describe how a spellchecker checks whether a word in a text file is correctly spelt or not.
-
19M.1.SL.TZ0.8:
State the part of the central processing unit (CPU) that is responsible for carrying out calculations.
-
19M.1.SL.TZ0.2:
Identify two features of a graphical user interface (GUI).
- 19M.1.SL.TZ0.15b: State the purpose of persistent storage on the computers.
-
18M.1.SL.TZ0.4:
Explain the importance of the memory management function of an operating system.
-
18M.1.SL.TZ0.5:
Construct a logic diagram for the following Boolean expression.
-
21M.1.SL.TZ0.5:
Calculate the denary (base 10) equivalent of the hexadecimal number BF.
-
17N.1.SL.TZ0.11a:
Describe how a spellchecker checks whether a word in a text file is correctly spelt or not.
-
17N.1.SL.TZ0.11c:
Identify two additional features of a word processing package that could be useful for this office.
-
18N.1.SL.TZ0.2a:
Outline what is meant by a database management system.
-
18N.1.SL.TZ0.8a.ii:
Outline the function of an operating system in managing primary memory.
-
18N.1.SL.TZ0.8c.ii:
State how many integers could be represented in this byte.
-
18N.1.SL.TZ0.8d:
Construct a truth table with two input variables. If the input variables are equal the value of the output variable should be True, otherwise it should be False.
-
19N.1.SL.TZ0.4b:
State the number of bits used to represent a non-primary colour, such as yellow.
-
19M.1.SL.TZ0.15a:
Identify two characteristics of RAM.
-
20N.1.SL.TZ0.4c:
Outline the function of the memory address register (MAR).
-
19M.1.SL.TZ0.7:
Outline the purpose of the memory address register (MAR) in the central processing unit (CPU).
-
21M.1.SL.TZ0.11:
Construct the truth table for the following logic circuit:
-
18N.1.SL.TZ0.8a.i:
Distinguish between random access memory (RAM) and read only memory (ROM).
-
17N.1.SL.TZ0.8b:
Outline the role of the data bus and address bus in this process.
-
19N.1.SL.TZ0.3b:
Explain the purpose of cache memory.
-
18N.1.SL.TZ0.8c.iii:
Outline why this byte could not be used to represent characters such as those used in Chinese.
-
20N.1.SL.TZ0.8c.ii:
Explain how the operating system ensures that each customer’s data is secure when multiple users are accessing the data at the same time.
-
19N.1.SL.TZ0.3a:
State the function of the control unit (CU) in the central processing unit (CPU).
-
20N.1.SL.TZ0.4b:
State the part of the central processing unit (CPU) that performs the decoding.
-
20N.1.SL.TZ0.8c.i:
State where the customer data is held during the process of modifying their data.
-
17N.1.SL.TZ0.11d:
Outline the purpose of one application software package other than a word processing package that could be used in this office.
-
17N.1.SL.TZ0.6:
Construct a logic diagram for the Boolean expression
NOT A OR B AND C.
-
17N.1.SL.TZ0.9:
Define the term bit.
-
20N.1.SL.TZ0.4a:
State where the program is held.
-
20N.1.SL.TZ0.6:
Construct a truth table for the following logical expression.
(A XOR B) AND NOT C
-
18N.1.SL.TZ0.8b:
Explain the roles of the data bus and the address bus in the machine instruction cycle.
-
19N.1.SL.TZ0.4a:
State why hexadecimal numbers are frequently used in computing.
-
19N.1.SL.TZ0.4c:
State the maximum number of colours that can be represented in a computer pixel.
-
19N.1.SL.TZ0.5:
Copy and complete the following truth table where:
X = A XOR B
Y = A NOR C
Z = X OR NOT Y
