Units Of Information
Overview
A phone camera fills a memory card, a film download stalls at ninety per cent, a spreadsheet refuses to attach to an email. Every one of those everyday frustrations is the same question asked in different clothing: how much room does this take up, and how much room is there? Answering it needs one unit that everything else is built from, and a set of names for the very large multiples of that unit that real files actually reach.
This lesson gives you both. You will learn what a bit is and why it is the smallest piece of information there can be, why bits are handled in groups of eight, and the four prefixes this specification examines: kilo, mega, giga and tera. You will also learn something that trips up a lot of candidates and quite a few adults: there are two rival definitions of a kilobyte in circulation, and OxfordAQA has told you in writing which one it will use in your exam.
Objectives
- Know that:
- a bit is the fundamental unit of information
- a byte is a group of 8 bits.
- Know that quantities of bytes can be described using prefixes.
- Know the names, symbols and corresponding values for the decimal prefixes:
- kilo, 1 kB is 1,000 bytes
- mega, 1 MB is 1,000 kilobytes
- giga, 1 GB is 1,000 megabytes
- tera, 1 TB is 1,000 gigabytes.
Mind map
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Units Of Information. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- How many bits are there in one byte? A. 2 B. 4 C. 8 D. 16 Answer: C
- On the 9210 specification, how many bytes are there in 1 kB? A. 8 B. 100 C. 1,000 D. 1,024 Answer: C
- Which of these quantities is the largest? A. 800 kB B. 0.9 MB C. 7,000,000 bits D. 950,000 bytes Answer: B
- A file is 6,000,000 bytes. What is this in megabytes? A. 0.6 MB B. 6 MB C. 60 MB D. 6,000 MB Answer: B
- How many different patterns can be stored in 5 bits? A. 5 B. 10 C. 25 D. 32 Answer: D
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