MCQ Detailed View

Every person has a unique voice that can be recognized even without visual cues, such as in darkness or over a phone call. This ability is due to the quality of sound, a property that distinguishes one sound from another even if they have the same pitch, loudness, or frequency. Understanding Sound Quality:

• 
  

  Sound is produced by vibrations of vocal cords in the human throat.

  
  


• 
  

  Each person’s voice depends on several factors:

  
  
  
  
  • 
    

    Shape of the vocal cords

    
    
  
  
  • 
    

    Structure of the mouth and nasal cavity

    
    
  
  
  • 
    

    Resonance characteristics of the throat

    
    
  
  
  
  


• 
  

  These physical differences cause variations in the harmonic content of the sound, giving it a unique timbre or quality.

  
  

✅ Other Properties of Sound:

1. 
   

   Pitch: Depends on the frequency of vibration; tells whether the sound is high or low.

   
   


2. 
   

   Frequency: Number of sound wave vibrations per second, measured in hertz (Hz).

   
   


3. 
   

   Time period: The time taken for one complete wave cycle; related to frequency.

   
   


4. 
   

   Quality (Timbre): The characteristic that allows us to differentiate between two sounds of the same pitch and loudness, such as distinguishing two musical instruments or human voices.

   
   

✅ Why "Quality" is the Answer:

Even if two people speak at the same pitch and loudness, we can still recognize them because their voice quality (timbre) is unique. This is why in the dark, recognition of a person by their voice is possible.

❌ Incorrect Options:

• 
  

  Pitch: Not unique enough for each person.

  
  


• 
  

  Frequency: Same as pitch, does not provide individuality.

  
  


• 
  

  Time period: Only a measure of wave cycle duration.

  
  

✅ Final Answer:

The quality of sound allows us to recognize a person by their voice in the dark (Option 4).