1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
LekaFEV [45]
3 years ago
8

A spherically-spreading EM wave comes from a 104.0 W source. At a distance of 9.6 m, what is the intensity of the wave?

Physics
1 answer:
Nookie1986 [14]3 years ago
8 0

Answer:

Approximately 0.0898 W/m².

Explanation:

The intensity of light measures the power that the light delivers per unit area.

The source in this question delivers a constant power of \rm 104.0\; W. If the source here is a point source, that \rm 104.0\; W of power will be spread out evenly over a spherical surface that is centered at the point source. In this case, the radius of the surface will be 9.6 meters.

The surface area of a sphere of radius r is equal to 4\pi r^{2}. For the imaginary 9.6-meter sphere here, the surface area will be:

\rm 4\pi \times (9.6\; m)^{2} \approx 1158.12\; m^{2}.

That \rm 104.0\; W power is spread out evenly over this 9.6-meter sphere. The power delivered per unit area will be:

\displaystyle\rm  \frac{104.0\; W}{1158.12\; m^{2}}\approx 0.0898\; W\cdot m^{-2}.

You might be interested in
A regular polygon has angkes of size 150° each.how many side has the polygon​
emmasim [6.3K]

Answer: 12

Explanation:

ıf each interior is 150 degrees, then each exterior angle is 180–150 or 30 degrees. Hence the polygon has 360/30 = 12 sides

5 0
3 years ago
Consider a small frictionless puck perched at the top of a xed sphere of radius R. If the puck is given a tiny nudge so that it
MakcuM [25]

Answer:

Explanation:

Let the vertical height by which it descends be h . Let it acquire velocity of v .

1/2 mv² = mgh

v² = 2gh

As it leaves the surface of sphere , reaction force of surface  R = 0 , so

centripetal force = mg cosθ where θ is the angular displacement from the vertex .  

mv² / r = mg cosθ

(m/r )x 2gh = mg cosθ

2h / r = cosθ

cosθ = (r-h) / r

2h / r =  r-h / r

2h = r-h

3h = r

h = r / 3

5 0
3 years ago
Which of the following represents the greatest energy transition from a higher energy level to a lower one?
prohojiy [21]
You need to use Planck's law:
E = h·υ = (h·c)/λ

Without making all the calculations, a fraction is bigger than another when the denominator is smaller. Therefore you need to find the smallest wavelength (λ) which is 450nm.

You could also be helped by colors: in order of decreasing energy, you have blue - green - yellow - red.

In any case, the correct answer is a).
8 0
3 years ago
The howler monkey is the loudest land animal and, under some circumstances, can be heard up to a distance of 8.9 km. Assume the
Airida [17]

Answer:

\frac{I}{I_0}=113.68

Explanation:

P = Acoustic power = 63 µW

r = Distance to the sound source = 210 m

Acoustic power

P=IA\\\Rightarrow I=\frac{P}{A}\\\Rightarrow I=\frac{63\times 10^{-6}}{4\times \pi \times 210^2}

Threshold intensity = I_0=1\times 10^{-12}\ W/m^2

Ratio

\frac{I}{I_0}=\frac{\frac{63\times 10^{-6}}{4\times \pi \times 210^2}}{1\times 10^{-12}}\\\Rightarrow \frac{I}{I_0}=113.68

Ratio of the acoustic intensity produced by the juvenile howler to the reference intensity is 113.68

6 0
3 years ago
Describe The energy conversions that occur when coal is formed, and then burned to produce thermal energy.
svlad2 [7]

Answer:

When energy contained in coal is turned into heat, and then into electrical energy. As boiling water heated by the burning coal is cooled, steam forges from these cone-shaped cooling towers.

8 0
3 years ago
Other questions:
  • What is a resource that is constantly being replenish
    12·1 answer
  • An electric field exerts an electrostatic force of magnitude 1.5 x 10-14 newton on an electron within the field. what is the mag
    11·1 answer
  • How to calculate the velocity? the answer is 5.4 m/s I need the explication
    15·1 answer
  • Physical Science Pre-Test 2020-2021 Question: 1-10 The distance between Earth and the Moon was determined by measuring the time
    7·1 answer
  • during the course of songraphic exam, you notice lateral splaying of echoes in the far field. what can you do to improve the ima
    6·1 answer
  • A wave has a frequency of 40 he and a wavelength of 35m. What is the speed of the wave?
    9·1 answer
  • A tennis racket strikes a tennis ball with a force of 100 N. With what force
    15·1 answer
  • A 1200 N force acts on an object, resulting in an acceleration of 8.0 m/s2. What is the mass of the object?
    10·1 answer
  • A boiling liquid absorbs thermal energy (heat) at a rate of 450 W. The specific latent heat of vaporisation is 2.7 × 106 J / kg
    5·1 answer
  • Where should clouds form and why
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!