Exercise Mod. 7

You can find the questions in the CD, inside: Source data / Revision_ques folder.

Microprocessors are sometimes used in hospitals to monitor a patient on a life-support machine. Give one advantage of using a microprocessor over a doctor or nurse.

The microprocessor can work 24/7 with a more accurate result than a doctor and nurse.

The temperature and soil moisture of a greenhouse must be controlled and must remain in a certain range. The temperature must be kept between 5 °C and 30 °C and the soil must not get too dry. Describe in detail how a computer system could be used to monitor and control both temperature and soil moisture in the greenhouse. In your answer state what items of hardware or equipment would be needed.

1. The temperature sensor measure the temperature in greenhouse and it sends a signal to an ADC. 
2. The ADC sends a digital signal to the microprocessor (computer)
3. This compares the input with stored values and decides what action needs to be taken.
4. If temperature is too high (more than 30 °C), the computer sends a signal to a DAC to operate the motors to open valves to spray water.
5. If it is too low (below 5 °C), the computer sends a signal to switch on heater to dry.

A large town uses computerized traffic lights, controlled by a central computer.
Give two types of input used by the system.
Give two benefits of the system.

The two types of input used by the system are induction loop sensor to count the number of vehicles at each junction; timer to measure how long it takes a vehicle to clear the junction or the road.
The two benefits of the system are  helping the police to arrange the traffic; can work 24/7 and more accurate than human.

A spreadsheet could be used to produce a simulation model. Give a definition of a simulation model and state one example of where a simulation model could be used.
Give one advantage of using a simulation model.

A simulation is the creation of a model of a real system in order to study the behavior of the system. Example of simulation using spreadsheet in a financial planning model.
The advantage is less expensive than the real thing and can be used for various scenarios.

A school collects data from its computerized weather station.

1. Name three sensors that could be used in the computerized weather station
2. Give two different methods of permanently storing the weather data collected.
3. Give two different methods of presenting the weather data.
4. Give two results that could be obtained from analyzing the weather data collected.
5. Give two advantages of using the computerized weather station to collect data rather than using manual methods of collecting weather data.

The three sensors that could be used in the computerized weather station are temperature sensor, humidity sensor (hygrometer) and wind speed sensor (anemometer). You may add more like atmospheric pressure (barometer) or wind direction (wind vane).
Two different methods of permanently storing the weather data collected are printout (for example in graph/chart method), CD or Disc or Tape.
Two different methods of presenting the weather data are table, graph/chart or spreadsheet.
Two results that could be obtained from analyzing the weather data collected are average number or total number or minimum or maximum value.
The two advantages of using computerized weather station to collect data are 

• could be used for data logging 24/7.
• more accurate for readings, time intervals and recording.

 For the example of exam questions please click here.

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