A-Level Extension (Beyond GCSE)
This paper moves from standard recall to complex synthesis and reverse engineering. Questions marked A-Level contain logic not required for OCR J277.
Knowledge & Precision (AO1)
1. Which gate outputs 1 only when BOTH inputs are 1?
2. Identify the formal name for the OR operator.
Advanced Notation
Grade 93. Select the correct mathematical notation for:
P = NOT A AND B
3. Order of Operations: Which part of the expression P = NOT (A OR B) AND C is calculated FIRST?
4. Which statement about truth table rows is mathematically correct?
Complex Synthesis (AO2)
The "Exclusive" Logic
You are not given the expression. Instead, analyse the logic:
"Output
P is 1 only if A or B is 1, but NOT if both are 1."
| A | B | P |
|---|---|---|
| 0 | 0 | |
| 0 | 1 | |
| 1 | 0 | |
| 1 | 1 |
Reverse Engineering (AO3)
Build the Mystery Circuit
A-Level: NAND Gate
You are not given the expression. You are given the Behaviour (Truth Table).
Reverse engineer the circuit to match the outputs.
Target Behaviour:
Scenario Analysis (LO4)
The "Trap" Wording
System: A nuclear safety switch (Q) activates if:
- Temperature is High (A) AND Pressure is High (B)
- UNLESS the Manual Override (C) is active.
Which logic expression accurately represents this system?