AQA GCSE COMPUTER SCIENCE 8525/2 Paper 2 Computing concepts Version: 1.0 Final *Jun* IB/G/Jun23/E12 8525/2QUESTION PAPER & MARKING SCHEME/ [MERGED] Marl( scheme June 2023

GCSE COMPUTER SCIENCE 8525/2 Paper 2 Computing concepts Version: 1.0 Final *Jun* IB/G/Jun23/E12 8525/2 For Examiner’s Use Question Mark 1–6 7 8 9–10 11 12 13 14 15 16 TOTAL Thursday 25 May 2023 Afternoon Time allowed: 1 hour 45 minutes Materials • There are no additional materials required for this paper. • You must not use a calculator. Instructions • Use black ink or black ball-point pen. Use pencil only for drawing. • Answer all questions. • You must answer the questions in the spaces provided. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Do all rough work in this book. Cross through any work you do not want to be marked. Information • The total number of marks available for this paper is 90. Advice For the multiple-choice questions, completely fill in the lozenge alongside the appropriate answer. If you want to change your answer you must cross out your original answer as shown. If you wish to return to an answer previously crossed out, ring the answer you now wish to select as shown. Please write clearly in block capitals Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. GCSE COMPUTER SCIENCE Paper 2 Computing concepts CORRECT METHOD WRONG METHODS 2 *02* IB/G/Jun23/8525/2 Do not write outside the Answer all questions in the spaces provided. box 0 1 . 1 The number base 2 is called binary. Shade one lozenge to show which number base is called hexadecimal. [1 mark] A 6 B 8 C 10 D 16 0 1 . 2 Shade two lozenges to show the statements that are true about hexadecimal. [2 marks] A Hexadecimal can represent a greater range of numbers than binary. B Hexadecimal is easier for people to read than binary. C Hexadecimal is faster for a computer to process than binary. D Hexadecimal is more accurate than binary. E Hexadecimal takes less space in RAM than binary. F Hexadecimal takes less time to type than binary. 0 2 . 1 Convert the decimal number 171 into binary. [1 mark] 3 *03* Turn over ► IB/G/Jun23/8525/2 Do not write outside the box 0 2 . 2 Convert the hexadecimal number 2D into binary. You should show your working. [2 marks] Answer 0 3 Add together the following three binary numbers and give your answer in binary. [2 marks] 0 1 0 1 1 0 0 0 0 0 0 1 1 0 0 1 + 0 1 0 0 1 0 1 1 0 4 Convert bits to megabytes (MB). You should show your working. [2 marks] Answer MB 4 *04* IB/G/Jun23/8525/2 Do not write outside the box 15 0 5 Describe the binary shift that would be used to divide a binary number by four. [1 mark] 0 6 . 1 When a sound wave is converted to a digital form it is sampled. The sampling rate is measured in hertz (Hz). Define the term hertz. [1 mark] 0 6 . 2 A sampling rate of 20 000 Hz and a sample resolution of four bits is used to make a digital recording of a sound that lasts 50 seconds. What is the minimum file size of the recording in megabytes (MB)? You should show your working. [3 marks] Answer MB 5 *05* Turn over ► IB/G/Jun23/8525/2 Do not write outside the Turn over for the next question box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 6 *06* IB/G/Jun23/8525/2 Do not write outside the 0 7 box . 1 The term pixel is short for Picture Element. Define the term pixel. [1 mark] 0 7 . 2 Figure 1 shows a 5 pixel x 5 pixel image. A minimum colour depth of two bits is needed to store the image. Figure 1 Explain how the image in Figure 1 can be represented as a bitmap. [3 marks] 7 *07* Turn over ► IB/G/Jun23/8525/2 Do not write outside the box 8 0 7 . 3 A 10 pixel x 10 pixel image contains five different colours. Calculate the minimum file size, in bits, of this image when represented as a bitmap. You should show your working. [2 marks] Answer bits 0 7 . 4 A black and white image has been compressed using run length encoding (RLE). The first bit in each byte of the bit pattern represents the colour and the remaining seven bits of the byte represent the number of pixels in the run. The image has a run of 60 black pixels followed by a run of 30 white pixels and is represented by the bit pattern shown in Figure 2. Figure 2 0 0 1 1 1 1 0 0 1 0 0 1 1 1 1 0 Using the same RLE method, give the bit pattern for a black and white image that has a run of 64 white pixels followed by a run of 15 black pixels. Write your answer in Table 1. [2 marks] Table 1 8 *08* IB/G/Jun23/8525/2 Do not write outside the 0 8 box . 1 Define the term hardware. [1 mark] 0 8 . 2 Describe the role of each of the following components of a CPU: [3 marks] Clock Control unit Register 0 8 . 3 Give one reason why a CPU with two cores might perform faster than an equivalent CPU with only one core