Question 4 :
The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?

Question 5 :
A pendulum oscillates 40 times in 4 seconds. Find its frequency.

Question 7 :
The to and fro motion of an object is known as _______ motion.

Question 8 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1d0abf59b460d7261f333.jpeg' /> In the above figure an alarm bell is kept inside a vessel. A person standing close to it can distinctly hear the sound of alarm. Now if the air inside the vessel is removed completely how will the loudness of alarm get affected for the same person?

Question 9 :
State True or False: If the amplitude of vibration is large, sound is feeble.

Question 10 :
State True or False: The number of oscillations per second of a vibrating object is called its time period.

Question 13 :
In order to reduce the loudness of a sound we have to

Question 14 :
Time taken by an object to complete one oscillation is called __________.

Question 16 :
State True or False: Noise pollution may cause partial hearing impairment.

Question 19 :
The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?

Question 20 :
We have a stringed musical instrument. The string is plucked in the middle first with a force of greater magnitude and then with a force of smaller magnitude. In which case would the instrument produce a louder sound?