The primary reason a light bulb emits light is due to the heating of the resistance in the filament of the light bulb. In fact, the power dissipated in a resistor is given by
 $P=I^2 R$
where I is the current and R the resistance. The larger the resistance or the current in the resistor, the larger the power dissipated. Due to this dissipation of power, the temperature of the filament becomes very high, and the resistance becomes incandescent, emitting light.

5 0

3 years ago

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How do fossils provide evidence that evolution has taken place

zzz [600]

Fossils provide solid evidence that organisms from the past are not the same as those found today; they show a progression of evolution. Scientists calculate the age of fossils and categorize them to determine when the organisms lived relative to each other. Hope this helps

7 0

3 years ago

How long does it take light to travel 850 km in a vacuum? Answer in ms.(Express your answer to two significant figures.)

poizon [28]

Answer:

0.002833 sec

Explanation:

Speed of light in vacuum is $3\times 10^{8}m/sec$

Given distance = 850 km = 850×1000=850000 m

We have to calculate the time that light take to travel the distance 850 km

Time $T=\frac{distance }{speed}=\frac{850000}{3\times 10^8}=2.833\times 10^{-3}sec$

So the time taken by light to travel 850 km is 0.002833 sec

5 0

3 years ago