1
4 marks
4 marksConsider this logic expression.
X = ( A AND B ) OR ( B AND NOT C )
Complete the truth table from the given logic expression.
| A | B | C | Working space | X |
| 0 | 0 | 0 | ||
| 0 | 0 | 1 | ||
| 0 | 1 | 0 | ||
| 0 | 1 | 1 | ||
| 1 | 0 | 0 | ||
| 1 | 0 | 1 | ||
| 1 | 1 | 0 | ||
| 1 | 1 | 1 |
[4]
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Logic Expressions (CIE IGCSE Computer Science)
Topic Questions
24 marks
4 marksConsider the logic statement:
X = (((A AND B) OR (C AND NOT B)) XOR NOT C)
Consider the completed truth table for the given logic statement.
| Row number |
A | B | C | Working space | X |
| 1 | 0 | 0 | 0 | 0 | |
| 2 | 0 | 0 | 1 | 1 | |
| 3 | 0 | 1 | 0 | 0 | |
| 4 | 0 | 1 | 1 | 1 | |
| 5 | 1 | 0 | 0 | 0 | |
| 6 | 1 | 0 | 1 | 1 | |
| 7 | 1 | 1 | 0 | 0 | |
| 8 | 1 | 1 | 1 | 1 |
There are four errors in the truth table in the output (X) column.
Identify the four incorrect outputs.
Write the row number to identify each incorrect output.
Row ........................
Row ........................
Row ........................
Row ........................
[4]
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34 marks
4 marksConsider the given logic statement:
X = ((NOT (A NAND B)) OR (B NOR C))
Complete the truth table for the given logic statement.
| A | B | C | Working space | X |
| 0 | 0 | 0 | ||
| 0 | 0 | 1 | ||
| 0 | 1 | 0 | ||
| 0 | 1 | 1 | ||
| 1 | 0 | 0 | ||
| 1 | 0 | 1 | ||
| 1 | 1 | 0 | ||
| 1 | 1 | 1 |
[4]
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44 marks
4 marksConsider the logic statement:
X = (((A NAND B) NOR (B AND C)) OR C)
Complete the truth table for the given logic statement.
| A | B | C | Working space | X |
| 0 | 0 | 0 | ||
| 0 | 0 | 1 | ||
| 0 | 1 | 0 | ||
| 0 | 1 | 1 | ||
| 1 | 0 | 0 | ||
| 1 | 0 | 1 | ||
| 1 | 1 | 0 | ||
| 1 | 1 | 1 |
[4]
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54 marks
4 marksConsider the following logic statement:
X = ((B AND NOT A) XOR (A OR C))
Complete the truth table for the given logic statement
| A | B | C | Working space | X |
| 0 | 0 | 0 | ||
| 0 | 0 | 1 | ||
| 0 | 1 | 0 | ||
| 0 | 1 | 1 | ||
| 1 | 0 | 0 | ||
| 1 | 0 | 1 | ||
| 1 | 1 | 0 | ||
| 1 | 1 | 1 |
[4]
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64 marks
4 marksAn alarm, Y, sends a signal (Y = 1) when certain fault conditions in a chemical process are detected. The inputs are:
| Input | Binary value | Condition |
| A | 1 | acidity > 5 |
| 0 | acidity <= 5 | |
| T | 1 | temperature >= 120°C |
| 0 | temperature < 120°C | |
| S | 1 | stirrer bar ON |
| 0 | stirrer bar OFF |
The alarm, Y, returns a value of 1 if:
either temperature >= 120°C AND stirrer bar is OFF
or acidity > 5 AND temperature < 120°C
Complete the truth table for this alarm system.
| A | T | S | Y |
| 0 | 0 | 0 | |
| 0 | 0 | 1 | |
| 0 | 1 | 0 | |
| 0 | 1 | 1 | |
| 1 | 0 | 0 | |
| 1 | 0 | 1 | |
| 1 | 1 | 0 | |
| 1 | 1 | 1 |
[4]
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