# Exponent/Logarithm Problem Solving Help

• Mar 8th 2011, 10:58 PM
dondonlouie
Exponent/Logarithm Problem Solving Help
I have a couple of questions that i need help withh :
1. Suppose a radio is playing loudly at a sound level of 80 decibels. What decibel level would make the radio sound one-fourth as loud?

how are you suppose to start this question? you don't use the decibel scale do you?

2. Show that a sound with d decibels has intensity E0(10)^(d/10), where E0 is the intensity of a sound with 0 decibels.

I have no idea what that question is asking for. D:

• Mar 8th 2011, 11:21 PM
earboth
Quote:

Originally Posted by dondonlouie
I have a couple of questions that i need help withh :
1. Suppose a radio is playing loudly at a sound level of 80 decibels. What decibel level would make the radio sound one-fourth as loud?

how are you suppose to start this question? you don't use the decibel scale do you?

2. Show that a sound with d decibels has intensity E0(10)^(d/10), where E0 is the intensity of a sound with 0 decibels.

I have no idea what that question is asking for. D:

1. $E_0$ denotes the socalled stimulus threshold.

2. Have a look here: Weber
• Mar 8th 2011, 11:35 PM
dondonlouie
but how would you solve the questions? i don't know how to set up the formula
• Mar 8th 2011, 11:58 PM
earboth
Quote:

Originally Posted by dondonlouie
but how would you solve the questions? i don't know how to set up the formula

1. The noise of 80 dB is described by: $E_0 \cdot 10^{\frac{80}{10}}$

2. The increased noise is described by: $E_0 \cdot 10^{\frac{d}{10}}$

3. The ratio of both sound levels is:

$\dfrac{E_0 \cdot 10^{\frac{d}{10}}}{E_0 \cdot 10^{\frac{80}{10}}}=\dfrac54$

(Remark: $\frac54$ is one fourth more than 1)

4. Solve for d.

5. I'll leave the 2nd question for you.
• Mar 9th 2011, 12:01 AM
dondonlouie
thanks (: