Computers & Components (Cambridge (CIE) A Level Computer Science): Exam Questions

A security system has both a floodlight (very bright light) and an audio alarm.

The data from multiple sensors is analysed and used to:

• turn on the floodlight

• sound the audio alarm.

Sensors can be used to detect:

• if doors are open

• the external daylight level

• if people are detected within a set distance.

Complete the table to identify the most appropriate type of sensor for each scenario.

Explain whether the security system is an example of a monitoring system or a control system.

Embedded systems are used in many electronic devices.

Describe the drawbacks of embedded systems.

An embedded system has Dynamic RAM (DRAM).

Identify one benefit of using DRAM instead of Static RAM (SRAM) in an embedded system.

Give two differences between Erasable Programmable ROM (EPROM) and Electrically Erasable Programmable ROM (EEPROM).

A road bridge has a weight limit and a height limit for vehicles. For example, a vehicle must weigh less than 10000kg and must have a height of less than 3m.

The bridge has a warning system. If a vehicle is approaching the bridge and it exceeds one or both limits, a sign displays a warning telling the driver of the vehicle to stop.

The bridge warning system uses sensors to detect if a vehicle exceeds the limits.

Complete the table by identifying two different sensors that could be used by the system and describe how each sensor is used by the system.

Explain whether the bridge warning system is an example of a monitoring system or of a control system.

A memory buffer uses Dynamic RAM (DRAM).

Identify two differences between DRAM and Static RAM (SRAM).

Explain how a memory buffer is used when a computer is transferring data to its magnetic hard disk drive.

A car has an automatic braking system.

A sensor is used to measure the distance to objects that are in front of the car.

The car automatically brakes if an object is too close to the front of the car or the distance between the car and the object is decreasing too quickly. The closer the object is to the front of the car, the harder the car brakes so that the car slows down more quickly.

Explain the reasons why the automatic braking system of the car is a control system.

A video doorbell is attached to the front door of a house. The doorbell uses a motion sensor to detect when a visitor walks in front of the door. When the motion sensor is activated:

• The digital camera in the doorbell starts recording a video.

• A message is transmitted to a smartphone so that the person who lives in the house can watch the video.

The doorbell also has a button that can be pressed. When the button is pressed, a message is transmitted to a smartphone to play the doorbell sound.

The videos are stored on the doorbell’s internal secondary storage device and overwritten when the secondary storage device is full.

The video doorbell can be considered an example of an embedded system.

Identify two characteristics of the doorbell that suggest it is an embedded system.

State whether the video doorbell is a monitoring system or a control system. Justify your choice.

The video doorbell has both primary memory and secondary storage.

(i) Identify two items of data that the video doorbell will store in primary memory.

(2)

(ii) The video doorbell has a solid state (flash) secondary storage device.

Complete the table by writing the answer or answers to each statement about the principal operation of solid state (flash) memory.

(4)

(iii) The video doorbell uses a buffer.

Describe how the video doorbell will use the buffer.

(2)

A computer game is being designed that users will be able to play using a virtual reality (VR) headset.

Complete the description of the principal operation of a VR headset.

A headset can have one or two ................ that output the image to the user. The headset has speakers that output surround sound to give a realistic experience.

The user’s head movements are detected using a sensor.

This sensor is a ................ . The data is transmitted to a microprocessor that analyses the data to identify the ................ of movement. Some headsets use ................ that record the user’s eye movements for analysis.

The computer uses a buffer when transmitting data to the VR headset.

Explain how a buffer is used when data is transmitted between the computer and the VR headset.

The VR headset has Electrically Erasable Programmable Read Only Memory (EEPROM).

Explain the benefits of using EEPROM instead of other types of Read Only Memory (ROM) in the VR headset.

Robots are used to serve food and drink to customers at a restaurant.

A robot navigates through the restaurant to the table it is serving.

Complete the table by identifying two sensors that can be included in the robot and the purpose of each sensor in the navigation system.

The navigation system can be considered an example of a control system.

Describe how feedback is used in a control system.

The robot includes a touchscreen for the customer to make their payment.

Describe the principal operation of a touchscreen.

Describe what is meant by the Immediate Access Store (IAS) in a computer system.

Describe the principal operations of a 3D printer.

Describe the purpose of a temperature sensor within the 3D printer.

A 3D printer contains 1GB of Dynamic RAM (DRAM) to store print data.

State two advantages of the printer having Dynamic RAM instead of Static RAM (SRAM).

Explain the importance of feedback in a control system.

Give one example of an embedded system and explain why it is an example of an embedded system.

A factory makes chocolate bars.

The factory uses a conveyor belt that moves the products from one stage of production to the next stage.

An automated system counts the number of chocolate bars made at the end of production.

The system includes a sensor positioned above the conveyor belt.

Identify one appropriate type of sensor that can be used.

A second automated system removes chocolate bars with an incorrect weight from the production line.

Describe the role of an actuator in this second system.

The factory has many different machines with embedded systems.

(i) Identify two features of embedded systems.

(2)

(ii) Identify one drawback of embedded systems.

(1)

Describe the roles of the address bus, the data bus and buffers in the process of writing data to the optical disc reader/writer.

The program files are stored on a new hard disk after they have been downloaded.

Describe the reasons why a hard disk formatter is needed for the new

A laptop computer has Static RAM (SRAM).

A virtual reality headset and a laser printer are connected to the laptop.

Explain why Static RAM is used in the laptop instead of Dynamic RAM.

Identify two reasons for using Electrically Erasable Programmable ROM (EEPROM) in a virtual reality headset.

Describe how the laser printer makes use of a buffer.