Are your headlight lenses getting cloudy 2430On Thu, 1 Sep 2005, Rick (etc.) You're right. Lens haze sharply reduces seeing light and sharply increases glare light. Federal Motor Vehicle Safety Standard 108 -- Lamps and Reflective Devices -- specifies UV...
fbloogyudsr
It's not an analogy. It is another example.
Yes - so you restrict the measruement of output to what is useful - visible light. If IR is not useful to you in the application, then it is part of the lost (wasted) energy. What's so hard about understanding that concept.
AND ULTIMATELY ENDS UP AS HEAT WHEN ALL IS SAID AND DONE. THE CAR ULTIMATELY STOPS DUE TO THE KINETIC ENERGY (ENERGY OF MOTION) BEING CONVERTED INTO HEAT BY BRAKES, BEARINGS, TIRES, AIR. IT IS A FACT. If a car moves from one point ot another (coming to rest) without a net change in elevation, 100% of the energy that was extracted from that fuel ended up in the environment as heat - a law of physics.
The ***ONLY*** exception to the above is if at the end of the trip, the car is higher level (elevation) than when it started - THEN - THEN AND ONLY THEN - is some of the energy not converted to heat - it went into producing the technical term called work (the change in elevation - force over distance). But when it comes down to the height at which it started, it needs that much less energy from the fuel (and ultimately heat) to get there.
Here's something for you to thnik about: regenerative braking.
That's a good thing. Efficiency is used in a similar way.
Another thing to think about: An engine on a dynamometer. The efficiency would be the energy measured at the output of the crankshaft compared to the energy in the fuel. The dynamometer measures this output at the crankshaft by putting a brake on the crankshaft that it turns against (that's why it is called "brake horsepower"). The energy produced at the crankshaft is turned into heat. A car moves, but the same amount of energy is eventualy converted into heat by all the friction that eventually brings the car to a stop (either gradually, or more quickly by use of the brakes).
Plus they generate some heat. So if the desired output is visible light, then everything else is disregarded in any kind of efficiency or efficacy measurement or calculation. However if the desired goal is for the bulb to produce heat and not light (a heat lamp), then the light is considered waste energy and is not considered as useful output, but the heat is. IOW - The if heat is the desire, then an incandescent bulb has high efficacy or high efficiency, but a flourescent has low efficacy or low efficiency. If visible light is the desire, then the opposite is true. What's plugged into the equation depends on the desired effect.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
