Understanding Computers: Unit Exam B
What each component does, more binary conversions, ordering units of storage, colour in pixels, sound sampling and ASCII.
Instructions
- Time allowed
- 25 minutes
- Total marks
- 25
- Calculator
- No calculator is permitted.
- Answer all the questions.
- The number of marks for each question is shown in brackets. Use it as a guide to how much to write.
- The clock at the top counts down from the real time allowed. When it reaches zero the paper is locked and marked, as it would be collected in the exam hall.
- Read every question to the end before answering. Where a question says tick two boxes, tick exactly two: ticking more than asked scores nothing. Type one word and number answers carefully, because they are marked exactly.
Questions
Answer every question, then finish the paper to have it marked. Marking as you go teaches you far less.
Tick one box.
- LD RAM
RAM holds whatever is running at the moment.
Tick one box.
- LC Microphone
A microphone puts sound into the computer.
| CPU | RAM | Storage | Graphics card | |
|---|---|---|---|---|
| Carries out instructions | ||||
| Holds open programs while they run | ||||
| Keeps files permanently | ||||
| Creates the images sent to the screen |
Tick one box in each row.
- LCarries out instructions: CPU
- LHolds open programs while they run: RAM
- LKeeps files permanently: Storage
- LCreates the images sent to the screen: Graphics card
The CPU processes, RAM holds running programs, storage keeps files, and the graphics card draws the picture.
- L12
- L16
- L255
- L1001
1100 = 8 + 4 = 12. 10000 = 16. 1111 1111 = 255. 9 = 8 + 1 = 1001.
- L8
2 x 2 x 2 = 8, from 000 to 111.
Tick one box.
- LC 8 bits
A byte is 8 bits.
| Smallest | Largest | |||
|---|---|---|---|---|
- Lbit, then byte: bit, byte
- LKB, then MB, then GB: KB, MB, GB
bit, byte, kilobyte, megabyte, gigabyte. Each step up is about a thousand times bigger, except that a byte is 8 bits.
Tick one box.
- LB 2
One bit has two values, 0 and 1, so two colours, such as black and white.
- LMore samples capture more detail of the sound wave
- LSo the recording is closer to the original sound, although the file is bigger
Each sample is one measurement of the sound wave. Taking more of them each second records more of the detail of how the wave changes, so the recording is closer to the original sound, although the file is bigger.
Tick one box.
- LA Gives each character a binary number so text can be stored
ASCII is a character set: A is 65, B is 66, and so on, each stored in binary.
- L3000
3 x 1000 = 3000 bytes.
| True | False | |
|---|---|---|
| RAM is volatile | ||
| The CPU keeps files when the computer is switched off | ||
| Binary uses only the digits 0 and 1 | ||
| A bit is bigger than a byte |
Tick one box in each row.
- LRAM is volatile: True
- LThe CPU keeps files when the computer is switched off: False
- LBinary uses only the digits 0 and 1: True
- LA bit is bigger than a byte: False
RAM loses its contents without power. The CPU does not store files. Binary has two digits. A byte is 8 bits.
- LIt is the main circuit board of the computer
- LIt connects the components, such as the CPU, RAM and storage, so they can communicate
The motherboard is the main circuit board. The CPU, RAM, storage and expansion cards plug into it, and its circuits carry data between them so they can work together.
This is an original Key Stage 3 assessment. Most questions are closed, so the marking is exact, and the written answers are marked against a mark scheme in the same style as a GCSE paper, so the format is familiar long before it counts.