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Les langues disponibles
Measurements
Power level indicator
Réf :
282 009
ENGLISH
2.2.4 Ecological lamp (ref. 332 016)
2.2.4
Note:
Note:
Two experiments can be carried out:
Two experiments can be carried out:
•
st
1
1
experiment: with the incandescent lamp unscrewed from its base,
experiment: with the incandescent lamp unscrewed from its base,
rotate the crank handle at about 1 turn/second, providing a certain
rotate the crank handle at about 1 turn/second, providing a certain
rotate the crank handle at about 1 turn/second, providing a certain
muscular effort (driving torque C1). The 9
muscular effort (driving torque C
•
nd
2
2
experiment: with the incandescent lamp screwed into its base, turn
experiment: with the incandescent lamp screwed into its base, turn
the crank handle, once again at about 1 turn/second, providing a
the crank handle, once again at about 1 turn/second, providing a
the crank handle, once again at about 1 turn/second, providing a
«different» muscular effort (driving torque C2). The 4
«different» muscular effort (driving torque C2).
Obviously, the
Obviously, the muscular effort supplied under load is greater than it was at no
muscular effort supplied under load is greater than it was at no
load: C2 > C1. And yet only four LEDs light up!
: C2 > C1. And yet only four LEDs light up!
In the 1st experiment, the power level indicator provides information about the
In the 1st experiment, the power level indicator provides information about the
In the 1st experiment, the power level indicator provides information about the
available power (potential), while in the second experiment i
available power (potential), while in the second experiment i
available power (potential), while in the second experiment it indicates the real
supplied power.
supplied power.
The qualitative justification is that the muscular effort (mechanical energy) to
The qualitative justification is that the muscular effort (mechanical energy) to
The qualitative justification is that the muscular effort (mechanical energy) to
be supplied actually depends on the electrical energy
be supplied actually depends on the electrical energy consumed
is no lamp, there is no consumed electrical energy and therefore no
is no lamp, there is no consumed electrical energy and ther
is no lamp, there is no consumed electrical energy and ther
mechanical energy to be supplied (except for the energy basically to overcome
mechanical energy to be supplied (except for the energy basically to overcome
mechanical energy to be supplied (except for the energy basically to overcome
resistance and friction in the gear system).
resistance and friction in the gear system).
This qualitative approach can be extended to include daily realities:
This qualitative approach can be extended to include daily realities:
This qualitative approach can be extended to include daily realities:
-
Does a car use more fuel when its headlights are on?
Does a car use more fuel when its headlights are on?
Does a car use more fuel when its headlights are on?
-
Can «electricity» be stored?
an «electricity» be stored?
10
Incandescent lamp unscrewed
th
LED lights up.
LED lights up.
The 4
th
LED lights up
consumed. Thus if there
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