← IGCSE Computer Science Paper 1

Writing exam answers about automated systems

Use these terms in order in an exam answer: the sensor reads, the microprocessor compares and decides, the actuator acts. Tie each point to the scenario and explain it with 'because'.

Part of: IGCSE Computer Science 0478 — 6.1 Automated Systems — Module 51

Understanding Writing exam answers about automated systems in IGCSE Computer Science Paper 1

What it does: The sentence follows the order sensor, reading, microprocessor, actuator and names each part correctly. Both an advantage and a disadvantage are given, each uses 'because' and each is linked to the scenario. An actuator is an output device that causes movement or action. A sensor only captures data from the environment. A full-mark point gives a specific reason linked to the scenario. The second answer is vague and repeats itself. When a question asks for both, you must give both sides. Leaving one out means you cannot get full marks. The actuator does not compare or decide. The microprocessor makes the decision and then signals the actuator.

Common mistakes: The microprocessor compares the reading with the stored value, not the actuator. Line 3 should say: It compares with set value. The actuator only acts in step 4. The reason is a general point and is not tied to the scenario. It should link the power cut to the system, for example: because the pump stops working.

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This module's key terms are also in a printable crossword (Modules 618–631) and word search (Modules 608–631).

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Learning
Duo
A question asks how an automated greenhouse waters plants. Which answer follows the correct order?
The moisture sensor reads the soil, the microprocessor compares it with the stored value, and the actuator turns on the water pump.The actuator reads the soil, the sensor compares it with the stored value, and the microprocessor turns on the water pump.
Matches
The actuator measures the temperature and sends it to the microprocessor.
↓
Sensor and actuator are confused: the sensor measures and the actuator is the output device that acts, such as a heater or motor.
Applying
Meanings
Term
sensor, microprocessor, actuator
Meaning
Use these terms in order in an exam answer: the sensor reads, the microprocessor compares and decides, the actuator acts. Tie each point to the scenario and explain it with 'because'.
Practice
The moisture sensor reads the soil moisture.
Testing
Gaps
The reads the temperature.
Check Answer
Spots
2Data goes to microprocessor
3Actuator compares the value

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Quick Questions

1. A question asks how an automated greenhouse waters plants. Which answer follows the correct order?
A. The actuator reads the soil, the sensor compares it with the stored value, and the microprocessor turns on the water pump.
B. The moisture sensor reads the soil, the microprocessor compares it with the stored value, and the actuator turns on the water pump. ✓
The order is sensor (reads), microprocessor (compares and decides), actuator (acts). Mixing up the parts loses marks.
2. Which part of an automated system physically carries out an action, such as opening a valve?
A. Sensor
B. Actuator ✓
An actuator is an output device that causes movement or action. A sensor only captures data from the environment.
3. Which sentence shows the best use of 'because' in an exam answer about automated street lights?
A. The lights switch on automatically because the light sensor detects that it is getting dark. ✓
B. The lights are good because they are good for the town.
A full-mark point gives a specific reason linked to the scenario. The second answer is vague and repeats itself.
4. An exam question says: 'Describe the advantages and disadvantages of automated traffic lights.' What should your answer include?
A. At least one advantage and at least one disadvantage, each linked to traffic lights. ✓
B. Only advantages, because they are the most important part.
When a question asks for both, you must give both sides. Leaving one out means you cannot get full marks.
5. Which answer is tied to the scenario of an automated farm irrigation system?
A. It works through the night because the sensors keep checking soil moisture without a farmer being present. ✓
B. Automated systems are faster than people and are used a lot nowadays.
The second answer is a general point that could apply to anything. Exam answers must refer to the scenario given.

Match the Pairs

sensor, microprocessor, actuator → The correct order to describe a system: the sensor reads, the microprocessor compares and decides, then the actuator acts
... because it is safe for workers → A reason linked to the scenario, which turns a bare point into a developed exam point
Describing a greenhouse system in order using the correct terms → The moisture sensor sends a reading to the microprocessor, which compares it with the stored value and switches on the sprinkler actuator.
Giving an advantage and a disadvantage tied to the scenario, each with a reason → Advantage: the robot works all night because it does not get tired. Disadvantage: a power cut stops the factory because the system needs electricity.
The actuator measures the temperature and sends it to the microprocessor. → Sensor and actuator are confused: the sensor measures and the actuator is the output device that acts, such as a heater or motor.
Automation is good because it is better and faster than people. → A general point not tied to the scenario: it names no system and gives no specific reason.

Key Term

sensor, microprocessor, actuator
Use these terms in order in an exam answer: the sensor reads, the microprocessor compares and decides, the actuator acts. Tie each point to the scenario and explain it with 'because'.

Fill in the Blanks

1. The sensor reads the temperature.
Hint: Type the input component that measures the environment and takes the reading.
2. The microprocessor compares the reading with the stored value.
Hint: Type the processing component that compares the reading and decides what to do.
3. The actuator opens the window.
Hint: Type the output component that carries out the physical action.
4. It heats up because the room is too cold.
Hint: Type the linking word that introduces the reason for the point.
5. Sensor, then microprocessor, then actuator.
Hint: Type the middle stage of the process order that processes the reading.

Spot the Error

Question 1
A Temp sensor reads the heat
B Data goes to microprocessor
C Actuator compares the value
D Heater actuator switches on
Line C — The microprocessor compares the reading with the stored value, not the actuator. Line 3 should say: It compares with set value. The actuator only acts in step 4.
Question 2
A Advantage: waters at night
B because sensors never tire
C Disadvantage: power cut
D because machines are bad
Line D — The reason is a general point and is not tied to the scenario. It should link the power cut to the system, for example: because the pump stops working.
Question 3
A Light sensor reads the dark
B Microprocessor sees low value
C Sensor switches the lamp on
Line C — Sensor and actuator are confused. A sensor only reads data. The actuator is the part that switches the lamp on.
Question 4
A IR actuator detects a person
B Microprocessor checks the data
C Motor actuator opens the door
Line A — The first step is the sensor reading the input. An actuator does not detect anything. It should be: IR sensor detects a person.
Question 5
A Sensor reads the pressure
B Reading goes to microprocessor
C Compares it with the actuator
D Actuator sounds the alarm
Line C — The microprocessor compares the reading with a stored (pre-set) value, not with an actuator. It should be: Compares it with stored value.

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