Computer Science
Computer systems — Paper 1
- 1.
Convert the denary number 45 to 8-bit binary. Explain why an 8-bit unsigned integer cannot store the value 300.
[4 marks] · no calculator - 2.
A school allows students to connect personal devices to its wireless network. Explain two security measures the school should use and how each reduces risk.
[4 marks] · no calculator - 3.
A smart doorbell should sound an alert if EITHER the button is pressed OR the motion sensor detects movement. Identify the logic gate that matches this behaviour, explain why, and state its output when the button input is 0 and the sensor input is 1.
[3 marks] · no calculator - 4.
A photographer needs to store very large video files and keep an off-site backup accessible from any location with an internet connection. Recommend a suitable storage solution and justify your choice.
[4 marks] · no calculator - 5.
Convert the hexadecimal value 2F to denary.
[3 marks] - 6.
Explain the role of the Program Counter (PC) in the fetch-execute cycle.
[2 marks] · no calculator - 7.
A company wants to email a large image file. Explain the difference between lossy and lossless compression, and state which is more appropriate if image quality must be preserved exactly.
[3 marks] · no calculator - 8.
A sound is sampled at a sample rate of 44,100 Hz for 10 seconds, using 16-bit samples and a single (mono) channel. Calculate the uncompressed file size in bits.
[3 marks] - 9.
Add the two 8-bit binary numbers 00001101 and 00000110. Give your answer in binary.
[3 marks] - 10.
Explain how a character such as the letter 'A' is represented inside a computer, referring to a character encoding system such as ASCII.
[2 marks] · no calculator - 11.
Distinguish between RAM and ROM in a computer system.
[2 marks] · no calculator - 12.
Explain the purpose of cache memory in a computer system.
[2 marks] · no calculator - 13.
Explain one advantage of a solid-state drive (SSD) over a traditional hard disk drive (HDD) for storing a laptop's operating system.
[2 marks] · no calculator - 14.
Explain one function that an operating system performs to manage a computer's hardware resources.
[2 marks] · no calculator - 15.
Explain the purpose of utility software, using anti-virus software as an example.
[2 marks] · no calculator - 16.
Distinguish between a high-level programming language and a low-level programming language.
[2 marks] · no calculator - 17.
Distinguish between a compiler and an interpreter as methods of translating high-level program code.
[2 marks] · no calculator - 18.
Complete the truth table logic for an AND gate: state the output when input A = 1 and input B = 0, and the output when input A = 1 and input B = 1.
[2 marks] · no calculator - 19.
Explain what a NOT gate does to a single binary input signal.
[1 mark] · no calculator - 20.
A logic circuit combines an AND gate feeding into a NOT gate: the AND gate takes inputs A and B, and its output becomes the single input to the NOT gate. Calculate the final output when A = 1 and B = 1.
[2 marks] · no calculator - 21.
Explain how a digital image is made up of pixels, and how resolution affects image quality.
[2 marks] · no calculator - 22.
An image uses a colour depth of 4 bits per pixel. Calculate the total number of different colours that can be represented by each pixel.
[2 marks] - 23.
Explain what is meant by an embedded system, using the computer inside a washing machine as an example.
[2 marks] · no calculator - 24.
Using 8-bit two's complement, convert the denary value −5 to binary.
[3 marks]