The correct option is (c) 2 and 3 only.
Explanation
Pitch is a characteristic of sound that distinguishes a shrill sound from a grave or flat sound. It is directly dependent on the frequency of vibration of the source producing the sound. Frequency refers to the rate at which the sound wave oscillates.
Statement-wise Analysis
- Statement 1 is Incorrect. Pitch is determined by the frequency of the emitted sound, not the amplitude. The amplitude of a sound wave determines its loudness or intensity. A sound with a larger amplitude is louder, while a sound with a higher frequency has a higher pitch.
- Statement 2 is Correct. Frequency is defined as the number of complete oscillations per unit time. In the context of a longitudinal sound wave, this corresponds to the number of compressions (or rarefactions) passing a fixed point per unit time. Therefore, a higher number of compressions passing a point indicates a higher frequency, which corresponds to a higher pitch.
- Statement 3 is Correct. The frequency of a sound wave is generated by the vibration of the source object. The faster the source vibrates, the higher the frequency of the sound wave produced. Consequently, a faster vibration results in a higher pitch (e.g., a whistle), whereas a slower vibration results in a lower pitch (e.g., a drum).
Key Takeaway
Pitch is determined by frequency (faster vibration = higher pitch), whereas Loudness is determined by amplitude (larger amplitude = louder sound).