Need help to find intensity of waves.

In summary, the conversation discusses the calculation of the intensity of waves emitted from a tiny vibrating source at different distances. The first part of the question involves using the equation I = P/A to calculate the intensity at two different distances. The second part involves finding the rate at which energy is leaving the source. The correct answer requires converting units and considering the actual surface area of the sphere rather than the area of 3.25cm2 where the energy is received.
  • #1
aldam3a
1
0

Homework Statement



A tiny vibrating source sends waves uniformly in all directions. An area of 3.25 cm2 on a
sphere of radius 2.50 m centered on the source receives energy at a rate of 4.20 J/s.

(a) What is the intensity of the waves at 2.50 m from the source and at 10.0 m from the
source?

(b) At what rate is energy leaving the vibrating source of the waves?



2. The attempt at a solution

I attemped the first part of the question using this equation :

I = P / A
A = 4 Pi r^2

so I = 4.2 / 4 * Pi * (2.5)^2 = 0.053

I asked my supervisor and he told me that my answer is wrong.

Any one who knows how i can go through this question ?
Thanks in advance
 
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  • #2
The power of 4.2J/s is passing through an area of 3.25cm2...not the surface area of the sphere.
I think you should also give intensity as W/m^2 so you will need to convert units to do that.
 

FAQ: Need help to find intensity of waves.

1. What is the definition of intensity of waves?

The intensity of a wave is the amount of energy that is transferred per unit time through a unit area perpendicular to the direction of wave motion. It is typically measured in watts per square meter (W/m^2).

2. How is the intensity of waves calculated?

The intensity of waves can be calculated using the equation I = P/A, where I is the intensity in watts per square meter, P is the power of the wave in watts, and A is the cross-sectional area of the wave in square meters.

3. Can the intensity of waves be measured directly?

No, the intensity of waves cannot be measured directly. It can only be calculated using the above equation or by using specialized instruments such as a radiometer or a calorimeter.

4. What factors affect the intensity of waves?

The intensity of waves is affected by the amplitude of the wave, the distance from the source of the wave, and the medium through which the wave travels. The type of wave also plays a role, as different types of waves have different equations for calculating intensity.

5. Why is knowing the intensity of waves important?

Knowing the intensity of waves is important for many reasons. It allows us to understand the behavior of waves and their effects on their surroundings. It also helps in the design and development of technologies that utilize wave energy, such as communication devices and medical equipment. Additionally, the intensity of waves is used in various fields, including acoustics, optics, and seismology.

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