The pitch of a note is not affected by

Step 1: Analyze the question We need the factor that does NOT affect the pitch of a note.

Step 2: Concept

• Pitch is how high or low a note sounds. It depends on the frequency of the sound wave. Higher frequency means higher pitch.
• Loudness depends on the amplitude of the wave.
• Quality (timbre) depends on the harmonics or overtones present.

For a vibrating string, the frequency is given by:

f = (1/2L) × √(T/μ)

where L is the length, T is the tension, and μ is the mass per unit length.

Step 3: Check each option

• A. Frequency: Pitch is determined directly by frequency, so it does affect pitch.
• B. Tension: Increasing T increases f, so the pitch rises. It does affect pitch.
• C. Mass of the string: A greater mass (greater μ) lowers f, so the pitch drops. It does affect pitch.
• D. Amplitude: Amplitude changes only the loudness (the energy carried), not the number of vibrations per second. It does not affect pitch.

Step 4: Answer The correct option is D. amplitude of sound wave.

Exam tip: Remember the pairs:

• Pitch → Frequency
• Loudness → Amplitude
• Quality → Waveform/overtones

If a question asks what does not change pitch, think "amplitude" first.