Lesson 4.5.6.7
4.5.6.7 Digital representation of sound Quiz: AQA Computer Science, Unit 5
20 questions
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Lesson 4.5.6.7, Digital representation of sound: 20 multiple choice questions for the AQA Computer Science (7517), Unit 5: Fundamentals of data representation, written with Revision Ninja.
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The 20 questions
-
What term defines the number of bits allocated per sound sample in audio recording?
- Nyquist frequency
- Sampling rate
- Bit rate
- Sample resolution
-
Which unit is used to measure the sampling rate of digital audio?
- Bits
- Decibels
- Bytes
- Hertz
-
According to the Nyquist theorem, what minimum sampling rate is needed to accurately sample a signal?
- Quadruple max frequency
- Half max frequency
- Double max frequency
- Equal to frequency
-
What is the standard frequency range of typical human hearing?
- 20 Hz to 200 kHz
- 200 Hz to 200 kHz
- 2 Hz to 2 kHz
- 20 Hz to 20 kHz
-
Which sampling rate is standard for CD-quality audio?
- 8 kHz
- 22.05 kHz
- 96 kHz
- 44.1 kHz
-
Which bit depth is standard for CD-quality audio?
- 16 bits
- 24 bits
- 8 bits
- 4 bits
-
What increases when the sample resolution of an audio file is increased?
- Sampling frequency
- Available amplitude levels
- Total duration
- Captured wave frequencies
-
A 10 second mono recording is made at 44.1 kHz with 16-bit samples. How many bytes does it need?
- 1,764,000 bytes
- 441,000 bytes
- 882,000 bytes
- 8,820,000 bytes
-
A 5 second mono recording is made at 8 kHz with 8-bit samples. How many bytes does it need?
- 80,000 bytes
- 400 bytes
- 40,000 bytes
- 5,000 bytes
-
A 1 minute mono recording is made at 22.05 kHz with 8-bit samples. How many bytes does it need?
- 132,300 bytes
- 1,323,000 bytes
- 13,230 bytes
- 2,646,000 bytes
-
A signal's highest frequency is 4 kHz. What is the lowest sampling rate that Nyquist allows?
- 8 kHz
- 4 kHz
- 16 kHz
- 2 kHz
-
What is the minimum sampling rate for a sound containing 15 kHz?
- 15 kHz
- 45 kHz
- 7.5 kHz
- 30 kHz
-
A sample resolution of 12 bits gives how many amplitude levels?
- 12
- 8192
- 1024
- 4096
-
If the sampling rate of an audio file is doubled, what happens to its file size?
- It quadruples
- It stays constant
- It doubles
- It halves
-
A 2 second mono recording is made at 16 kHz with 8-bit samples. How many bits does it need?
- 256,000 bits
- 32,000 bits
- 128,000 bits
- 512,000 bits
-
A 9 kHz audio tone is sampled at 12 kHz. What false alias frequency is produced?
- 9 kHz
- 3 kHz
- 6 kHz
- 15 kHz
-
Why does increasing the bit depth of a sound recording reduce quantisation noise?
- Smaller rounding errors
- Higher sample rate
- Fewer recorded samples
- Fewer amplitude levels
-
A 30 second stereo recording is made at 48 kHz with 24-bit samples. Which size is closest?
- About 0.9 MB
- About 2.9 MB
- About 17.3 MB
- About 8.6 MB
-
What unwanted effect occurs when a signal is sampled at less than twice its highest frequency?
- Quantisation noise
- Clipping
- Frequency shift
- Aliasing
-
Why is a sampling rate of 44.1 kHz used for CD audio quality?
- Matches speaker hardware
- Captures human hearing
- Reduces file size
- Prevents quantisation noise
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