η = 13.8 lm/W. The luminous efficacy of a incandescent lightbulb that produces 830 lumens and consumed a power of 60 W is 13.8 lm/W.
The luminous efficacy of a light source is the relationship between the luminous flux (in lumens) emitted by a light source and the power (in watts). The luminous efficacy of a light source or luminous efficiency measures the part of electrical energy that is used to illuminate and is obtained by dividing the luminous flux emitted by the electrical power consumed. Luminous efficiency is expressed in lumens per watt (lm / W). It is given by the relation:
η = F / P. Where F is the luminous flux, and P is the power consumed by the light source.
The efficacy of a 60.0 W incandescent lightbulb that produces 830 lm is:
η = 830 lm / 60 W
η = 13.8 lm/W
The weight of the load is (mass) x (gravity)
= (350 kg) x (9.8 m/s²)
= 3,430 newtons .
The force on the surface of the liquid is the weight of the piston and its load.
The pressure on the surface of the liquid is (force) / (area)
= (3,430 newtons) / (1 m²)
= 3,430 pascals
= 3.43 kPa
This doesn't include anything for the weight of the piston without its load,
but it's certainly the closest of the choices.
Snowshoes enable a person to walk on depp snow because the snowshoes increase the area over which the person´s wight is distributed.
b.increase the area over which the person´s wight is distributed.
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