A: Calculating Photon Count from Electrical Energy and Efficiency

In summary, the conversation discusses the efficiency of a sixty-watt incandescent light bulb in converting electrical energy into light energy. It also considers the number of photons emitted by the bulb and how many photons would enter the eye if someone were to look at the bulb from a distance of 3.5 meters for 0.10 seconds. The equations used are E=hf and the conversion of angstroms to wavelength. The first question to answer is how many Joules per second are produced in the form of visible light, and the second question is how many Joules of energy are in one photon.
  • #1
wildredhead
8
0

Homework Statement


In converting electrical energy into light energy, a sixty-watt incandescent light bulb operates at
about 2.2% efficiency. Assuming that all of the light is green light (wavelength approximately
5500 Å), determine the number of photons per second given off by the bulb and B:if you were to look directly at the bulb, the light
from it would travel directly to your eye without reflecting from anything. If you stand 3.5
meters away and look at the bulb for only 0.10 seconds, how many photons will enter your eye?
(assume the pupil of your eye has a diameter of 2.1 mm)


Homework Equations


I don't really know what to use.
I think E= hf


The Attempt at a Solution


First I converted angstroms to wavelength then I found frequency. From frequency and planks constant I found E but then I got nothing . DOn't even know how to touch B.
 
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  • #2
For (A), you need to answer two questions first:

1. How many Joules per second are produced in the form of visible light?

2. How many Joules of energy are in one photon? (Use the answer you got from using E=hf)
 

Related to A: Calculating Photon Count from Electrical Energy and Efficiency

What is the photoelectric effect?

The photoelectric effect is the phenomenon where electrons are ejected from a material when it is exposed to light of a certain frequency.

Who discovered the photoelectric effect?

The photoelectric effect was discovered by German physicist, Albert Einstein, in 1905.

What is the significance of the photoelectric effect?

The photoelectric effect provided evidence for the particle-like nature of light, supporting the idea of photons. It also led to the development of quantum mechanics and the understanding of the relationship between light and matter.

What factors affect the photoelectric effect?

The frequency and intensity of the incident light, as well as the material's work function and surface properties, can affect the photoelectric effect.

How is the photoelectric effect used in technology?

The photoelectric effect is used in various technologies such as solar cells, photodiodes, and photoelectric sensors. It is also the basis for the functioning of devices such as photocopiers and digital cameras.

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