How Can I Prove My Coloured Light Results Align with Planck's Constant?

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Homework Help Overview

The original poster investigates the relationship between colored light and energy transfer, aiming to demonstrate that their results align with Planck's constant. They reference the equation E=hf and express a desire to plot energy against frequency using measurements from an experiment involving a lamp and colored filters.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the context of the measurements (I, V, time, temperature rise, wavelength) and seek clarification on the experimental setup. The original poster describes their practical setup and the temperature measurements for different colored lights, while others question the assumptions made about frequency and energy transfer.

Discussion Status

The discussion is ongoing, with participants exploring various interpretations of the results and the implications of the original poster's findings. Some guidance has been offered regarding the complexities of the experiment and the need for careful consideration of the filters used.

Contextual Notes

There are uncertainties regarding the definitions of the measurements and the experimental conditions, particularly concerning the behavior of different colored filters and their impact on energy transfer.

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My physics essay is on coloured light.

after investigating i found that the higher level frequency light red yellow transferred more energy

this is due to E=hf.

now i want to prove my results coincide with Plancks constant.
i want to plot E against f, the gradient should be h.
i have I,V, time, temperature rise and wavelength.
what equation do i need to get Energy.
 
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That all depends on what the context of I, V, time, temperature rise and wavelength is. Care to elaborate?
 
ok this was my pratical.

i connected a powerpack to a lamp and placed a coloured filter on top, with ammeters and voltmeters attached.

i put a thermometer 5 cm away fom the lamp and measured the temperature rise. the

red light heated the thermometer up the most followed by yelow green and blue.

this was because E=hf and red has the highest frequency. i have the results but how do i find the Eneregy transferred so i can plot it on a E versus f graph?
 
i measeured the temp rise for 10 minutes each
 
There are a number of things to clarify here.

1. Red light has the lowest frequency, and longest wavelength, in the visible spectrum.

2. If this is an ordinary incandescent lamp, it produces more power at red wavelengths than at blue. This simple fact explains the different temperatures you measured.

3. The filters you used could be transmitting different amounts of incident light. For example, the red filter might transmit wavelengths between 630 and 700 nm, while the blue filter might transmit between 470 and 480 nm. This would lead to more heating with the red filter, simply because a larger range (70 nm) of wavelengths are transmitted than for the blue filter.

To do what you are trying, you would need an experiment that allows a fixed number of photons, no matter what the wavelength, to be absorbed by the thermometer. I don't know just how one would accomplish this, but it would be a very complicated and expensive experiment to do.
 

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