omputer-science/aqa/questions","basePath":"/gcse/computer-science/aqa/representing-sound/questions","formulaUrl":null,"initialIndex":17,"initialQuestionWindow":[{"id":"614d3734-9beb-4d96-9df7-a3ab6a8379b6","revisionId":"2719f854-a677-4cef-bb97-0935acd7e74a","questionNumber":null,"questionType":"LA","specification":"A marine biologist is using a single-channel hydrophone to record underwater vocalizations of blue whales. The recording device is configured with a sampling rate of 16 kHz and a sample resolution of 24 bits.","difficulty":4,"difficultyBand":"medium","totalMarks":4,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"4499456d-a923-4e2d-9d13-e9ba5d0bc23a","label":null,"content":"Calculate the minimum file size of a 1.5-minute audio recording. Give your answer in bytes.\n\nYou should show your working.","markscheme":"- Converts units to standard base units: $1.5\\text{ minutes} = 90\\text{ seconds}$ and/or $16\\text{ kHz} = 16,000\\text{ Hz}$ B1\n- Shows multiplication of the correct parameters to calculate total size: $16,000 \\times 24 \\times 90$ (or $16,000 \\times 3 \\times 90$) M1\n- Shows conversion from bits to bytes by dividing the total bits by 8: $\\frac{34,560,000}{8}$ (or by converting 24 bits to 3 bytes beforehand) M1\n- State the correct final answer of $4,320,000\\text{ bytes}$ A1","marks":4,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"7ea51bc1-a85d-4cb8-b4aa-03b07bfbe98b","revisionId":"9f48528b-a7df-4146-99e3-685c75386562","questionNumber":null,"questionType":"LA","specification":"A marine research hydrophone records a mono audio track of a whale song lasting 4 minutes and 10 seconds. The recording is made with a sample rate of 96 kHz and a sample resolution of 24 bits.","difficulty":5,"difficultyBand":"medium","totalMarks":2,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"7715525c-20a1-4a54-9df8-1d41a3005200","label":null,"content":"Calculate the file size of the uncompressed audio track in **megabytes (MB)**.\n\nShow your working.","markscheme":"- Calculates the total duration in seconds ($250\\text{ s}$) and converts 24 bits to 3 bytes, then multiplies to find the file size in bytes: $250 \\times 96,000 \\times 3 = 72,000,000\\text{ bytes}$ (or in bits: $250 \\times 96,000 \\times 24 = 576,000,000\\text{ bits}$) M1\n- Converts bytes to megabytes to give a final answer of **72 MB** (using $10^6$ bytes per MB) or **68.66 MB** / **68.7 MB** (using $2^{20} = 1,048,576$ bytes per MB) A1","marks":2,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"978e77ec-7113-4741-bd9a-401624f1baf3","revisionId":"4512e5d9-6c3a-40ee-a6fb-8afd10ad8cbe","questionNumber":null,"questionType":"LA","specification":"A podcaster is recording a short audio intro. The recording software uses a sampling rate of 3,000 Hz and a sample resolution of 12 bits.","difficulty":3,"difficultyBand":"medium","totalMarks":4,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"321dda07-cd68-4695-be42-ee7de6427e75","label":null,"content":"Calculate the minimum file size of a 10-second audio recording. Give your answer in bytes.\n\nYou should show your working.","markscheme":"- Shows correct multiplication of values: $3,000 \\times 12 \\times 10$ M1\n- Calculates the correct size in bits: $360,000$ bits A1\n- Shows division by 8 to convert to bytes: $360,000 \\div 8$ M1\n- Obtains the correct final answer: $45,000$ bytes A1","marks":4,"order":0,"markingRubric":null,"explanation":null,"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null}],"subjectCode":"gcse_computer_science__aqa","summaries":[{"id":"00e5fca2-2c20-4361-ad53-2845355ff80c","difficultyBand":"medium","calculatorUse":null},{"id":"03757f99-c78e-4c15-95d2-7d246d64b845","difficultyBand":"medium","calculatorUse":null},{"id":"091f2

Representing sound

Question 7

Representing sound Questions

Representing sound

Question 7

Representing sound Questions