Solar collector efficiency

Hi there,

As part of my A2 physics coursework investigation, i want to calculate the efficiency of an aluminium canister modelled as a solar collector.

The basic set up of the apparatus is:

- Lamp (40W light bulb) at a fixed distance of 5cm away from the aluminium canister (which is painted black, and the half of the canister not being penetrated by light is covered with insulating material - carpetty)

What measurements need to be taken? Can you provide me with a step-by-step guide of how to calculate the efficiency with equations.

Thanks a lot!


You want a step by step guide of how to do your coursework with equations?

How about reading your recommended text and talking to your teacher?
No its not actually my coursework investigation, and isnt really required, but i want to do this anyway...

Its not in the textbooks, nor the A2 syllabus, but it shows that i have researched, which i have...


No-one's going to give you a step by step guide of how to do an experiment. Ask a specific question about something you're unable to grasp.

Efficiency = useful power output / total power input

What is your useful output? Heat?
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A common calculation related to the intensity of a light source is to figure that a detector gathers some of the source's energy on a particular surface area, and that area is a known fraction of the area of an imaginary sphere surrounding the source and capturing all of its energy. A common astronomy exercise is: a detector orbiting the earth measures electromagnetic radiation from the sun to be 1370 watts per square meter, now, using a reference table to obtain the distance from the earth to the sun, imagining the sun to be enclosed by a sphere whose radius is the sun-earth distance, we can determine that the sun puts a total of 3.8 X 10^26 watts.

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