Physics, 26.07.2019 00:00 tts313

What is the difference between energy and intensity as far as light waves are concerned? how would you change the energy? how would you change the intensity? are these changes independent of one another? why or why not?

Answers: 1

Show answers

Answers

Answer from: baileytmyers01

1) A light wave consists of many photons, each photon carrying an energy equal to
E=hf

where h is the Planck constant and f is the light frequency, so the energy of the wave is given by the frequency of the light.

The intensity of a light wave is instead the power P developed by the wave per unit of surface A:
$I= \frac{P}{A}$
where the power is actually the ratio between the total energy of the wave and the time:
$P= \frac{E_{tot}}{t}$
and so, the intensity is
$I= \frac{E_{tot}}{At} = \frac{Nhf}{At} = nE$
where N is the total number of photons emitted (and so, the total energy is just the number of photons N times the energy of a single photon E), and $n= \frac{N}{At}$ is the number of photons emitted per unit of time and unit of area.

2) How would you change the energy?
As we saw in point 1), the energy of the light is given by
E=hf

So, we can see that we can change the energy of the light wave by changing its frequency, f.

3) How would you change the intensity?
The formula for the intensity was:
I= nE

and so, we can see that we can change the light intensity either by changing the number of photons emitted per seconds per squared meters (n), or by increasing the energy of the photons E (so, by changing the frequency of the light)

4) Are these changes independent of one another? Why or why not?
They are not completely independent, because we see from the previous formula that the intensity also depends on the energy E. However, it is possible to change energy without changing the intensity, and viceversa, looking again at the two formulas:
E=hf

- we can change the energy by changing the frequency of the light, and we can change the number of photons emitted n such that the product nE remains constant, so the intensity I remains constant.
- we can change the number of photons emitted n, so the intensity I changes, but we can keep the frequency of the light constant, so that the energy does not change.

Answer from: Quest

answer: a) y=-8x+5

a) m= -8

b) m= -2

c) m= 7

d) m= 6

Answer from: Quest

increasing transnational kinetic energy. because the transnational kinetic energy formula consists of only two variables, mass and velocity, increasing one of those properties is the only way to increase an object's transnational kinetic energy. increases to mass and velocity, however, do not have the same impact.

Another question on Physics

Physics, 22.06.2019 05:20

A3.9 g aluminum foil ball with a charge of +4.1×10−9 c is suspended on a string in a uniform horizontal e⃗ field. the string deviates to the right and makes an angle of 30∘ with the vertical. part a part complete what information about the e⃗ field can you determine for this situation? what information about the field can you determine for this situation? only the magnitude of e⃗ only the direction of e⃗ both the magnitude and the direction of e⃗ none of the above previous answers correct part b determine the magnitude of the electric field. express your answer with the appropriate units. e e = nothing nothing request answer part c determine the direction of the electric field. determine the direction of the electric field. to the right to the left away from you toward you

Answers: 3

Answer

Physics, 22.06.2019 15:50

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.

Answers: 2

Answer

Physics, 22.06.2019 21:00

If the specific heat of a metal is 0.850 j/g °c, what is its atomic weight?

Answers: 2

Answer

Physics, 22.06.2019 21:00

Ais a machine that makes work easier when a single force is applied. a simple machine b compound machine c endangered machine d complex machine

Answers: 2

Answer

You know the right answer?

What is the difference between energy and intensity as far as light waves are concerned? how would...