13 marksmedium
An image is stored on a computer. The image is 16‑bit colour and is 100 pixels high and 150 pixels wide.
Calculate the file size of the image in bytes.
Show all your working.
Computer Science
22 questions · 84 marks · ≈ 1 hour · spans 22 of 30 topics
Assembled from the topic question banks — not an official Cambridge International paperAn image is stored on a computer. The image is 16‑bit colour and is 100 pixels high and 150 pixels wide.
Calculate the file size of the image in bytes.
Show all your working.
Binary numbers are stored in registers.
Negative denary numbers can be represented as binary using two’s complement.
Complete the binary register for the denary number –78
You must show all your working.
Extract:
The Unicode character set is used to represent text that is typed into a computer.
One disadvantage of using the Unicode character set, instead of the ASCII character set, is that the text stored takes up more storage space.
Give one reason why it takes up more storage space.
A company is setting up both wireless and wired networks for secure communication between employees. The IT team must ensure that all data transmitted across the networks is encrypted.
Describe how encryption protects data transmitted over wireless networks.
In your answer explain:
Identify two reasons why errors can occur when using wireless technology to transmit data.
A student has a sound file that is too large to be stored on their external secondary storage device. The student compresses the sound file to make the file size smaller.
The student sends the sound file to a friend. The file is transmitted across a network that uses packet switching.
Explain how the file is transmitted using packet switching.
A computer has a Von Neumann architecture
Describe the purpose of the control unit (CU) within this computer.
Three types of storage media are magnetic, optical and solid state
One example of solid‑state storage is a Solid State Drive (SSD).
Identify one other example of solid‑state storage.
A farmer uses an automated robot to plant seeds in the field.
The robot plants seeds and stops when it reaches a fence. It then turns and continues planting seeds. The robot uses sensors and a microprocessor to know when it reaches a fence.
Explain how the robot uses sensors and a microprocessor to know it has reached a fence
A user wants to connect their computer to a network.
Identify the component in the computer that is needed to access a network
Identify the type of address that is allocated to the component by the manufacturer, which is used to uniquely identify the device.
A dynamic internet protocol (IP) address is allocated to the computer when it is connected to the network.
Identify the device on the network that can connect multiple devices and automatically assign them an IP address.
A programmer uses a low‑level language to write a computer program for a vending machine.
Describe what is meant by a low‑level language.
Explain the role of peripheral management in the operating system.
Include how it facilitates plug-and-play (PnP) functionality
A student uses the internet for their schoolwork to research what is meant by pharming.
State the aim of pharming.
Digital currency can be used to buy products from the world wide web.
State what is meant by a digital currency.
A student uses the internet for their schoolwork to research what is meant by pharming.
The student uses a web browser to access data on the internet.
State the purpose of the web browser.
An expert system is an example of artificial intelligence. One component of an expert system is a knowledge base.
Explain why an expert system needs a knowledge base.
A factory uses an automated system to control the temperature of its storage rooms.
The system consists of temperature sensors, a microprocessor, and actuators connected to heaters and cooling units. The sensors monitor the temperature and send the data to the microprocessor. The microprocessor processes the data and activates the heaters or cooling units based on pre-programmed rules.
Explain how the automated system maintains the desired temperature in the storage rooms.
Extract:
A factory uses an automated system to control the temperature of its storage rooms. The system consists of temperature sensors, a microprocessor, and actuators connected to heaters and cooling units. The sensors monitor the temperature and send the data to the microprocessor. The microprocessor processes the data and activates the heaters or cooling units based on pre-programmed rules.
Discuss two advantages and two disadvantages of using such an automated system in the factory.
Robots are used in a factory to build cars.
One characteristic of a robot is its mechanical structure.
State two other characteristics of a robot.
Suggest two advantages of using robots, instead of humans, to build cars in the factory.
The one-dimensional (1D) array StudentName[] contains the names of students in a class. The two-dimensional (2D) array StudentMark[] contains the mark for each subject, for each student. The position of each student’s data in the two arrays is the same, for example, the student in position 10 in StudentName[] and StudentMark[] is the same.
The variable ClassSize contains the number of students in the class. The variable SubjectNo contains the number of subjects studied. All students study the same number of subjects.
The arrays and variables have already been set up and the data stored.
Students are awarded a grade based on their average mark.
| Average mark | Grade awarded |
|---|---|
| greater than or equal to 70 | distinction |
| greater than or equal to 55 and less than 70 | merit |
| greater than or equal to 40 and less than 55 | pass |
| less than 40 | fail |
Write a program that meets the following requirements:
calculates the combined total mark for each student for all their subjects
calculates the average mark for each student for all their subjects, rounded to the nearest whole number
outputs for each student:
calculates, stores and outputs the number of distinctions, merits, passes and fails for the whole class.
You must use pseudocode or program code and add comments to explain how your code works.
You do not need to initialise the data in the array.
A satellite navigation system is an example of a computer system that is made up of sub-systems.
Part of a satellite navigation system:
Draw a structure diagram for this part of the satellite navigation system.
Tick (✓) one box to identify the first stage of the program development life cycle.
Choose your answer
Analysis
Coding
Design
Testing
An algorithm has been written in pseudocode to input some numbers. It only outputs any numbers that are greater than or equal to 100. The number 999 is not output and stops the algorithm.
INPUT Number
WHILE Numbers <> 999 DO
IF Number > 100
THEN
OUTPUT Number
ENDIF
ENDWHILE
OUTPUT Number
Identify the four errors in the pseudocode and suggest corrections.
Extract:
An algorithm has been written in pseudocode to input some numbers. It only outputs any numbers that are greater than or equal to 100. The number 999 is not output and stops the algorithm.
INPUT Number
WHILE Numbers <> 999 DO
IF Number > 100
THEN
OUTPUT Number
ENDIF
ENDWHILE
OUTPUT Number
The four errors in the pseudocode are:
Numbers
IF Number > 100
INPUT Number missing from inside the loop
The final OUTPUT Number is not needed
Write a pseudocode statement to change the corrected algorithm to output all numbers between 100 and 200 inclusive.
You do not need to rewrite the whole algorithm