ITPEC FE Morning April 2020 Question 25
ITPEC FE Morning April 2020 — Question 25 of 80
Audio recording time calculation — compute max recording duration from memory size and sample rate.
Given:
- Sample size: 8 bits = 1 byte
- Sampling rate: 11,000 samples/sec
- Flash memory: 512 × 10⁶ bytes
Step-by-step:
- Data rate = 11,000 samples/sec × 1 byte = 11,000 bytes/sec
- Time in seconds = 512,000,000 ÷ 11,000 ≈ 46,545.45 sec
- Time in minutes = 46,545.45 ÷ 60 ≈ 775.76 → 775 minutes
Why not others:
- (a) 77 — off by a factor of 10
- (b) 96 — likely unit confusion (bits vs bytes)
- (d) 969 — incorrect divisor
Key rule: Data rate = sampling_rate × bits_per_sample / 8. When bits_per_sample = 8, each sample is exactly 1 byte. Max time = memory_size / data_rate, then convert to the requested unit.
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