To solve this problem it is necessary to apply the concepts related to Sound Intensity. The unit most used in the logarithmic scale is the decibel and mathematically this is expressed as

Where,
= Sound intensity level in decibels
I = Acoustic intensity on the linear scale
Hearing threshold
According to the values, the total intensity is 32 times the linear intensity and the value in decibels is 83dB
So:




Therefore the sound intensity due to one person is 67.948dB
Answer:
Option a
Explanation:
The action of the rapid rubbing of the hands are a result of chemical reaction and responses that takes place inside our body.
When we rub our hands together, that shows the mechanical motion of the body or we can say that while rubbing hands chemical energy gets converted to mechanical energy (here, Kinetic energy).
While rubbing, due to friction, heat is produced and hence we can say that this mechanical energy has transformed to heat energy.
Thus the conversion here is from chemical to mechanical to heat energy.
Answer:
3.) 463 J/g
Explanation:
Heat given by the fuel is used to increase the temperature of the water
so it is given as

here we will have
m = 250 g

now we also know that

so we have


so 3.5 g fuel gives above energy
so per gram of fuel will have total energy given as


Answer:
A total of 150 joules of work was done
Explanation: