FaroukYasser
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Homework Statement
A heater with a variable power is surrounded by ice in a funnel. The heater is turned on on 70W and the ice starts melting. once the rate of dropping of droplets is constant. The mass of water falling is then calculated for 5 minutes and it is found that 0.26 g/s falls every second. The experiment is repeated for 110W for 5 minutes also and the mass is found to be 0.38 g/s, Find:
1) The latent heat of fusion of ice in J/g
2) The heat gained from the surrounding per second
Homework Equations
Energy supplied by heater + heat gained from surrounding = mass * latent heat of fusion or in symbols:
E + h = mL
The Attempt at a Solution
Okay so I am having two ideas to solve this and I am not sure which one I should choose:
Method 1:
For the first time with 70 W.
E + h = mL
(70x1) + h = 0.26L (Equation 1)
For the second time with 110 W
(110x1) + h = 0.38L (Equation 2)
Equation 2 - Equation 1
40 = 0.12L >>>> L = 333 J/g to 3s.f
subbing in L into any equation. h = 16.7 J/s (W)
Method 2
L = E/m
using the first value once. L = 70/0.26 = 269.2
using second valiue of L = 110/0.38 = 289.5
Average is 279 J/gWhich method should I use?. does method one have any flaws and if so what are they. does Method 2 have any flaws and if so what is it?
Thanks in advance :)