Audacity

1- What is a sound?
A form of energy.
2- What is the speed of sound?
340.29 m / s
3- What is faster, the speed of light or the speed of sound?
Speed of light.
4- How do you record a sound?
With a microphone.
5- What is the difference between digital and analog sound?
The key difference between analog and digital technologies is that analog technologies record waveforms as they are, while digital technologies convert analog waveforms into sets of numbers, recording the numbers instead. When played back, the numbers are converted into a voltage stream that approximates the original analog wave.
6- Write 3 advantages of digital sound over analog sound?
Unlike digital audio systems, analog systems do not require filters for bandlimiting.

One aspect that may prevent the performance of practical digital systems from meeting their theoretical performance is jitter. This is the name given to the phenomenon of the variations in spacing of the discrete samples in time within the stream of samples that make up a (decoded) digital signal. This can be due to timing inaccuracies of the digital clock. Ideally a digital clock should produce a timing pulse at exactly regular intervals.

Analog systems do not have discrete digital levels in which the signal is encoded. Consequently, the original signal can be preserved to an accuracy limited only by the intrinsic noise-floor and maximum signal level of the media and the playback equipment, i.e., the dynamic range of the system. With digital systems, noise added due to quantization into discrete levels is more audibly disturbing than the noise-floor in analog systems.
7- What are the factors that determine the quality of digital sound?
The sample rate and the sample format
8- What audio file formats does Audacity support?
AUP;IRCAM;WAV;MPEG;AIFF;Ogg Vorbis
9- Write the difference between PCM audio files and Compressed ones?
The PCM is every number on a digital audio file represents a waveform. In the compressed by algorithms that are able to squeeze the waveforms in less space.
10- Write examples of each one of them.
MP3: compressed Wav: PCM