YAPhysicsT: Thermodynamics

[Ricemarine]

So the question is

- A laser can deliver 1.6 * 10^13 watts of power in 2.5 ns.
- Compare the energy output for one time interval to the energy amount of heating 0.8 kg water from 20 degrees C to 100 degrees C.

So, for the laser, [1.6 * 10^13 j/s (watts)] * [2.5*10^-9 s] = 40 kJ.

As for the water.
(4180 K J/kg)(.8kg)(80 celsius) = 267.52 kJ

So my question is... how am I supposed to compare the energy output?... Just divide 40 kJ by 267.52 kJ?

 

[Fenixgoon]

you can take the ratio or subtract the two, it doesnt matter as long as you show that one is significantly greater than the other (IMO anyway)

 

[marketsons1985]

That's what I'd say too. It's ~ 1/4 of the energy needed to heat water....blah blah.

 

[Safeway]

Yea, just take a ratio. Eazy-cheezy.