Hey I have 3 questions to ask and I've done both of them, i just want to know if I did it right or wrong.
1. On September 26, 2001, an earthquake in North Bay measured 5.0 on the Richter scale. What is the magnitude of an earthquake 3 times as intense as North Bay's earthquake?
The answer I got was 5.477
2. How much louder is a mp3 player (100dB) to a crying baby (80dB)?
The answer I got was approx 10 (9.69)
3. A liquid has a pH of 3.46. Find the hydrogen ion concentration [H+].
The answer I got was 10^-3.64 which is .000229
Basically the work for this process I did:
PH = -logH^+
H^+ = 10^-3.64
H^+ = .000229
So are these answers right? For the last one did I show the correct process? Thanks
To do these you are supposed to know something about the Richter scale, the relationship between a sound level in dB and intensity and the relationship between pH and concentration of H+ ions.
A sound level is related to the intensity by:
where is the reference intensity for the sound level type in question (the reference levels used in air and underwater are different).
Now if two sound levels differ by dB we have:
But the definition of sound level in dB in terms of intensities will be (should) in your notes or text book somewhere.
(how much louder means how much greater in the sound intensity in the two cases)