That they sometimes explode?
A) Pitch depends on the frequency of a sound wave. The higher the pitch, the higher the frequency and the lower the pitch, the lower the frequency. Sound waves have different pitches due to varying frequency levels.
B) Sound is created as the pen vibrates. This vibrations also interacts with the air atoms and molecules, causing them to vibrate too, therefore, creating sound waves. The reason the brain grows annoyed at this continual sound is because the brain will focus on this sound only, causing the brain to go into overdrive, creating annoyance.
C) Sound waves are travelling vibrations of particles. Space does not have any atoms or particles for the sound vibrations to interact with, therefore creating zero sound waves to travel.
Hope this helps!! :))
It is strong enough to penetrate through flesh but not bone so we can see if there are fractures or breaks in our skeleton
Answer:
Current will be 81.7 mA
Which is not given in bellow option
Explanation:
We have given capacitance 
Resistance R = 500 ohm
Voltage V = 12 volt
We know that time constant of RC circuit of RC circuit is given by

Time is given as t = 1 sec
We know that current in RC circuit is given by

So current 
Which is not given in the following option