Intensity of wave

[Raiden2012]

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Will be most increased by an increase in which of the following?

Wavelength
Amplitude
Density
Velocity

I = 0.5 * rho * omega^2 * A^2 * v
= 0.5 * rho * (2pi*f)^2 * A^2 * v
The answer is amplitude but I don't understand why it isn't v

f = v/lambda
so wouldn't v be to the power of 3 and thus bigger than the square of A?

 

[sciencebooks]

Will be most increased by an increase in which of the following?

Wavelength
Amplitude
Density
Velocity

I = 0.5 * rho * omega^2 * A^2 * v
= 0.5 * rho * (2pi*f)^2 * A^2 * v
The answer is amplitude but I don't understand why it isn't v

f = v/lambda
so wouldn't v be to the power of 3 and thus bigger than the square of A?

Lol, I also reasoned v but differently... I did so thinking I=P/A=Fv/A...

Was that equation you used in a passage with the question?

 

[Raiden2012]

It's a free standing question in the EK1001 book. We do not have to know the equation per se; it's just meant to improve foundational knowledge. We do have to know that intensity is proportional to square of amplitude though

 

[Jepstein30]

It's a free standing question in the EK1001 book. We do not have to know the equation per se; it's just meant to improve foundational knowledge. We do have to know that intensity is proportional to square of amplitude though

Yea i just know that intensity is proportional to the square of amplitude and the square of the angular frequency

 

[Raiden2012]

Yea i just know that intensity is proportional to the square of amplitude and the square of the angular frequency

yea but I still don't understand why the answer isn't v.

 

[sciencebooks]

yea but I still don't understand why the answer isn't v.

Hm, using the equation I used earlier, I=P/A=Fv/A, intensity would be proportional to v AND then also proportional to A^2 so then A would influence it more? (I don't know how you derived the proportionality to v^3 earlier though so that could be correct.)

 

[shaboobly]

Will be most increased by an increase in which of the following?

Wavelength
Amplitude
Density
Velocity

I = 0.5 * rho * omega^2 * A^2 * v
= 0.5 * rho * (2pi*f)^2 * A^2 * v
The answer is amplitude but I don't understand why it isn't v

f = v/lambda
so wouldn't v be to the power of 3 and thus bigger than the square of A?

from what you have here: I = 0.5 * rho * omega^2 * A^2 * v

v doesnt have a power and A does which means it will increase intensity the most.

 

[Raiden2012]

Yes but omega = 2pi*f where f = v/lambda
so it becomes v^2 * v

 

[shaboobly]

Yes but omega = 2pi*f where f = v/lambda
so it becomes v^2 * v

i see what you did.. i would just assume to only use what they give you and not take outside knowledge in and substitute any variables. but who knows what you did seems right to me with the math (if v is the same variable in both eqs) so it could just be a typo.

 

[sciencebooks]

Yes but omega = 2pi*f where f = v/lambda
so it becomes v^2 * v

Ohhh, I see what you were deriving now. Hm, good question. Could it have anything to do with velocity being the same in the same medium or some rule like that? What did the explanation give?

 

[Raiden2012]

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Ohhh, I see what you were deriving now. Hm, good question. Could it have anything to do with velocity being the same in the same medium or some rule like that? What did the explanation give?

Explanation
Looking at the equation, A is to the power of 2 and v is to the power of 1.

Which means they didn't take into account omega and I just want to know why
Test in 2 weeks, I'm so dead