CIE IGCSE COMPUTER SCIENCE:
SENSORS EXAM QUESTIONS WITH
COMPLETE ANSWERS
What are motion sensors used for? - Answer-● Security Systems - detect intruders
using microwaves
● Turning Lights on when someone enters the room (saves energy) and stops moving
● Automatic doors
● Gaming: Wii, Kinect
● Microbit & mobile phone use
Accelerometer (detects rotation and tilt)
What is a magnetic field sensor? - Answer-● Detect Changes in magnetic fields
● Measure strength and direction of
magnetic field
● Can respond to magnetic changes
● Earth's magnetic field: north,south,east
west
What are magnetic field sensors used for? - Answer-● Mobile phones have these:
magnetometers - allows phone to act as a compass
● Magnetic sensors in mobile phones also used to wake up/turn off a phone/tablet to
switch screen on with case
What is a gas sensor? - Answer-● Detects presence of Gas and responds if too
high/low
What are gas sensors used for? - Answer-● Used to detect carbon monoxide in
homes/offices etc
● Also used in many industries to detect toxic gases
What is a moisture sensor? - Answer-● Moisture measures how much liquid in a
material
● Humidity measures how much liquid in air
● Temperature is also measured
What are moisture sensors used for? - Answer-● Often used for soil when farming crops
● Best/level moisture in soil = better crops
● Automated watering can be used with these sensors
What is a humidity sensor? - Answer-● Hygrometer = humidity sensor
● Measure water vapour & temperature in
SENSORS EXAM QUESTIONS WITH
COMPLETE ANSWERS
What are motion sensors used for? - Answer-● Security Systems - detect intruders
using microwaves
● Turning Lights on when someone enters the room (saves energy) and stops moving
● Automatic doors
● Gaming: Wii, Kinect
● Microbit & mobile phone use
Accelerometer (detects rotation and tilt)
What is a magnetic field sensor? - Answer-● Detect Changes in magnetic fields
● Measure strength and direction of
magnetic field
● Can respond to magnetic changes
● Earth's magnetic field: north,south,east
west
What are magnetic field sensors used for? - Answer-● Mobile phones have these:
magnetometers - allows phone to act as a compass
● Magnetic sensors in mobile phones also used to wake up/turn off a phone/tablet to
switch screen on with case
What is a gas sensor? - Answer-● Detects presence of Gas and responds if too
high/low
What are gas sensors used for? - Answer-● Used to detect carbon monoxide in
homes/offices etc
● Also used in many industries to detect toxic gases
What is a moisture sensor? - Answer-● Moisture measures how much liquid in a
material
● Humidity measures how much liquid in air
● Temperature is also measured
What are moisture sensors used for? - Answer-● Often used for soil when farming crops
● Best/level moisture in soil = better crops
● Automated watering can be used with these sensors
What is a humidity sensor? - Answer-● Hygrometer = humidity sensor
● Measure water vapour & temperature in
