IGCSE Computer Science Paper-1: Specimen Questions with Answers 49 - 50 of 164

Question number: 49

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Describe how the sensors, microprocessor and door motors interact to ensure a passenger is not trapped in a closing door.

Explanation

The ultrasonic sound waves are being sent by radar based motion detectors which gets reflected back to the sensor. These reflected back waves triggers the sensor to send the signal and therefore an automatic door is opened.

Infrared Sensors can also be used for opening automatic doors by detecting a change in temperature. When the sensors detect a temperature that is warmer, representing a human it will activate the opening and closing mechanism of the door.

Question number: 50

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Define a Cursor in Database along with its types.

Explanation

A Cursor may be defined as the database object which helps in manipulating data row by row. This helps in representing a result.

There are mainly 3 types:

i) Dynamic Cursor: While scrolling it reflects changes.

ii) Static: It doesn’t reflect changes while scrolling. It works on recording of snapshots.

iii) Keyset: There is no reflection of new data during the Data Modification.

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