Data representation — IGCSE Computer Science (0478) questions by topic
Data representation questions cover ordering units of data storage, converting an 8-bit binary register into a denary parking cost, calculating a hexadecimal value, and explaining how reducing sample rate compresses a sound file. Calculate, give, state, identify and explain are the command words, with calculate requiring shown working through a defined conversion, not just a final figure.
26 real questions from 2023 to 2025 papers make up this page, worth 2 to 24 marks. Binary and hexadecimal conversions are exactly the kind of working where a single misplaced digit changes the whole answer, so submitting each conversion for instant marking catches an error, such as converting to denary instead of hexadecimal, before it repeats.
What examiners look for
- A recurring mistake is converting binary to denary instead of hexadecimal, and giving a vague reference to binary being what the computer understands rather than explaining its actual role.
- Examiners also flag describing sample resolution in relation to an image rather than sound, giving an example of compression such as MP3 rather than naming a compression type, and performing a binary shift to the right instead of the left.
- A further common mistake is converting values to denary, adding them, then converting back, rather than demonstrating binary addition directly.
- Strong answers calculated the correct parking cost of $17.70 and provided correct binary values throughout.
- Reports praise candidates who provided a correct hexadecimal number and who identified the correct compression method as lossless.
May–June 2025, Paper 11
The size of a file can be measured using different data storage units. Tick (✓) one box to show the smallest data storage unit. A byte B gibibyte (GiB) C kibibyte (KiB) D nibble
Answer this question and get it marked →An image is converted to binary to be represented by a computer. Complete the table with the missing terms and definition about representing an image. Term Definition --- ---…
Answer this question and get it marked →May–June 2024, Paper 11
Hypertext markup language (HTML) colour codes can be represented as hexadecimal. Tick (✓) one box to show which statement about the hexadecimal number system is incorrect. [ ] A…
Answer this question and get it marked →The binary number 10100011 is stored in random access memory (RAM). A logical left shift of three places is performed on the binary number. Give the 8-bit binary number that will…
Answer this question and get it marked →May–June 2024, Paper 12
Data can be measured in bits. Give the name of the data storage measurement that is equal to 8 bits.
Answer this question and get it marked →Binary is a base 2 number system. Give the name of the number system that is base 16.
Answer this question and get it marked →May–June 2024, Paper 13
The size of a file can be measured in different units. State how many bits there are in a byte.
Answer this question and get it marked →An image has a 16-bit colour depth and a resolution of 1000 × 1750 pixels. State what is meant by a 16-bit colour depth.
Answer this question and get it marked →A programmer is creating a computer game. One character is not moving correctly. The programmer needs to debug the program and look at addresses that are locations in memory. The…
Answer this question and get it marked →October–November 2024, Paper 11
The size of a file can be measured using different units. Tick (✓) one box to show which of these is not a unit of measurement for a file. [ ] A bit [ ] B bot [ ] C nibble [ ] D…
Answer this question and get it marked →A user enters text into a computer system, using a keyboard. An American standard code for information interchange (ASCII) character set is used to convert the text to binary.…
Answer this question and get it marked →October–November 2024, Paper 12
Data storage can be measured using different units of measurement. Identify the name of the smallest unit of measurement of data.
Answer this question and get it marked →A user enters data that is hexadecimal into a computer system. The data is converted to binary to be processed by the computer. Give one similarity between hexadecimal and binary.
Answer this question and get it marked →October–November 2024, Paper 13
Data can be measured using different units of storage. Tick (✓) one box to show which of the following is the largest unit of data storage. [ ] A tebibyte (TiB) [ ] B pebibyte…
Answer this question and get it marked →An employee has a report that they need to email to their employer. The employee compresses the report file before emailing it. State the effect the compression has on the report…
Answer this question and get it marked →May–June 2023, Paper 11
Binary is a number system used by computers. Tick (✓) one box to show which statement about the binary number system is correct. [ ] A It is a base 1 system [ ] B It is a base 2…
Answer this question and get it marked →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…
Answer this question and get it marked →May–June 2023, Paper 12
Binary numbers can be converted to hexadecimal. Convert the two binary numbers to hexadecimal. 10010011 = ........ 00001101 = ........
Answer this question and get it marked →When keys are pressed on a keyboard, the text is converted to binary to be processed by the computer. Describe how the text is converted to binary to be processed by the computer.
Answer this question and get it marked →May–June 2023, Paper 13
Computers store data as binary. The binary number 10101110 is stored. Convert the binary number to denary.
Answer this question and get it marked →October–November 2023, Paper 11
A car park has a payment machine that allows a customer to pay for their parking. The cost of parking is displayed as a denary number and stored in two 8-bit binary registers. For…
Answer this question and get it marked →A musician is recording herself playing the music for a song on the piano. Explain how the analogue sound is recorded and converted to digital.
Answer this question and get it marked →October–November 2023, Paper 12
A register stores the binary number: 1 1 1 0 0 0 1 1 Give the denary number for the binary number stored in the register.
Answer this question and get it marked →A band is recording their new song. They need to consider the sample rate and sample resolution of their recording. Give one benefit of using a higher sample rate to record the…
Answer this question and get it marked →October–November 2023, Paper 13
Humans use a denary number system and computers use a binary number system. Explain what is meant by a binary number system.
Answer this question and get it marked →A photographer takes an image with a digital camera. The photographer sets the resolution and colour depth for the image. State what is meant by the image resolution.
Answer this question and get it marked →Other IGCSE Computer Science topics
- Hardware (108)
- Algorithm design and problem-solving (43)
- The internet and its uses (23)
- Data transmission (21)
- Boolean logic (19)
- Databases (16)
- Automated and emerging technologies (13)
- Software (12)
- Programming (11)