IGCSE COMPUTER SCIENCE - UNIT #5
EXAM QUESTIONS WITH COMPLETE
ANSWERS
Surface Acoustic Wave screens - Answer-Two sound wave transducers (which
generate the ultrasonic sound) and two receivers are used; the sound waves travel
parallel to the edge of the glass vertically and horizontally, the position where the screen
is touched is detected by a reduction in the sound wave amplitude.
Types of sensor - Answer-Gas (e.g. oxygen, carbon dioxide), Infra-red (e.g. motion or
heat source), pH (i.e. acid or alkalinity), Light, Temperature, Magnetic field, Pressure,
Moisture/humidity, Acoustic (i.e. sound).
Monitoring and control of sensors - Answer-Monitoring will simply report the values and
inform users of the status of the process being monitored and controlling can alter how
the process is operating; in other words it can change the value of the next input
received by.
Detection systems - Answer-The pressure sensors monitor an intruder stepping on the
floor next to the windows, doors or on the floor next to valuable paintings, the acoustic
sensors pick up the sound of breaking glass or footsteps on the floor, the infra-red
sensors pick up movement in the rooms but also any changes in heat (e.g. heat
radiation from an intruder).
Sensor feedback - Answer-The microprocessor will have access to pre-set values for all
sensors, the microprocessor will sample each sensor at a given frequency (e.g. every 2
seconds), monitoring continues until the user keys in a PIN/passcode to deactivate the
system.
Chemical process - Answer-The temperature sensors and pH sensors constantly take
readings from the chemical process, the data is converted into digital format using an
ADC and is then sent to the computer, the computer has the pre-set values for
temperature and pH stored in memory.
Types of output devices - Answer-monitors, printers, speakers
Inkjet printers - Answer-Droplets of ink are produced using a thermal bubble
Behind hundreds of print nozzles there are tiny resistors that create heat (the
temperature momentarily exceeds 1000°C), A small piezoelectric crystal is located at
the rear of each ink reservoir of each nozzle.
Laser printers - Answer-run much faster because they use lasers to print
EXAM QUESTIONS WITH COMPLETE
ANSWERS
Surface Acoustic Wave screens - Answer-Two sound wave transducers (which
generate the ultrasonic sound) and two receivers are used; the sound waves travel
parallel to the edge of the glass vertically and horizontally, the position where the screen
is touched is detected by a reduction in the sound wave amplitude.
Types of sensor - Answer-Gas (e.g. oxygen, carbon dioxide), Infra-red (e.g. motion or
heat source), pH (i.e. acid or alkalinity), Light, Temperature, Magnetic field, Pressure,
Moisture/humidity, Acoustic (i.e. sound).
Monitoring and control of sensors - Answer-Monitoring will simply report the values and
inform users of the status of the process being monitored and controlling can alter how
the process is operating; in other words it can change the value of the next input
received by.
Detection systems - Answer-The pressure sensors monitor an intruder stepping on the
floor next to the windows, doors or on the floor next to valuable paintings, the acoustic
sensors pick up the sound of breaking glass or footsteps on the floor, the infra-red
sensors pick up movement in the rooms but also any changes in heat (e.g. heat
radiation from an intruder).
Sensor feedback - Answer-The microprocessor will have access to pre-set values for all
sensors, the microprocessor will sample each sensor at a given frequency (e.g. every 2
seconds), monitoring continues until the user keys in a PIN/passcode to deactivate the
system.
Chemical process - Answer-The temperature sensors and pH sensors constantly take
readings from the chemical process, the data is converted into digital format using an
ADC and is then sent to the computer, the computer has the pre-set values for
temperature and pH stored in memory.
Types of output devices - Answer-monitors, printers, speakers
Inkjet printers - Answer-Droplets of ink are produced using a thermal bubble
Behind hundreds of print nozzles there are tiny resistors that create heat (the
temperature momentarily exceeds 1000°C), A small piezoelectric crystal is located at
the rear of each ink reservoir of each nozzle.
Laser printers - Answer-run much faster because they use lasers to print
