Question

Fill in the blanks with the most appropriate option.
If a guitar string is pulled strongly, its amplitude of vibration ___(i)___ and the note heard is ___(ii)___, If it is pulled lightly, its amplitude of vibration ___(iii)___ and the note heard is ___(iv)___.

• A. (i)-decreases, (ii)-softer, (iii)-increases, (iv)-louder
• B. (i)-increases, (ii)-louder, (iii)-decreases, (iv)-softer
• C. (i)-increases, (ii)-softer, (iii)-decreases, (iv)-louder
• D. (i)-decreases, (ii)-louder, (iii)-increases, (iv)-softer

Answer 1

The correct option is B (i)-increases, (ii)-louder, (iii)-decreases, (iv)-softer

Loudness of a sound depends on the amplitude of the sound wave. When amplitude increases, loudness also increases and vice-versa.
When we pull the string of a guitar strongly, the string displaces more. Hence, its amplitude of vibration increases and the note heard is louder.
Also, when we pull the string of a guitar lightly, the string displaces less. Hence, its amplitude of vibration decreases and the note heard is softer.