Anita Sood, Anupama Bhandari, Madhabi Bose and, Shelly Wadhwa Solutions for Exercise 3: TRACK YOUR PROGRESS

Which part of the music instrument flute vibrates to produce sound?
(Choose one of the following: Air column/ Strings/ Shell).

Which part of the following instrument vibrates to produce sound?
Guitar

(Choose form here: air column, membrane, string)

Which part of the music instrument trumpet vibrates to produce sound?
(Choose one of the following: Air column/ Strings/ Shell of the Trumpet).

Answer in one word.
Audible range of frequencies for human beings.
($20 \mathrm{Hz}-20,000 \mathrm{Hz}$/$20 \mathrm{Hz}-20,000 \mathrm{kHz}$)

What is the frequency of infrasonic sound?
(Choose one of the following: below $20 \mathrm{Hz}$, above $20 \mathrm{Hz}$, above $20 \mathrm{kHz}$).

Answer in one word:
Part of human body that produces sound (larynx/ vocal cord).

Answer in one word.

Frequency of ultrasonic sound.

(Choose one of the following: Above $20 \mathrm{kHz}$/ Below $20 \mathrm{Hz}$).

Answer in one word.
Sound level which is comfortable for the human ear.

(Choose from: $20-350 \mathrm{dB}$/ $60-65 \mathrm{dB}$ )