It is true that the white and black keys produce different pitches when played. The white keys produce natural notes (A, B, C, D, E, F, and G), while the black keys produce sharps or flats (A#/Bb, C#/Db, D#/Eb, F#/Gb, and G#/Ab). However, the loudness or power of each note is not determined solely by its pitch.
When a key is pressed on a piano, a hammer strikes the corresponding string(s) inside the instrument, causing the strings to vibrate and produce sound. The force with which the key is pressed affects the speed and energy transferred to the hammer, influencing the volume of the sound produced. Regardless of whether a white or black key is played, the volume will depend on the力度 used by the pianist.
Additionally, the design and construction of the piano, including the tension and thickness of the strings, resonance of the soundboard, and the shape and size of the instrument's body, all play a role in the overall sound and loudness of each note.
Therefore, while the white and black keys on a piano produce different pitches, the power or loudness of each note is determined by a combination of factors such as the applied force, the piano's construction, and the acoustic properties of the individual notes.