- #1
TKrantz
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Homework Statement
I'm doing an investigation for my physics class, where we were told to investigate the relationship between current flowing through and the efficiency of an immersion heater. My hypothesis was that as current increased, the efficiency would decrease due to the relationship P=I^2R, where as current is doubled, the power loss would quadruple.
The way I conducted the experiment was to use a power pack connected to an immersion heater inside a calorimeter and measured the rise in temperature of the water over 2 minutes. I then raised the voltage, which increased the current and recorded the new change in temperature.
I then compared the heat absorbed by the calorimeter and the water inside it using the equation q=mcT versus the actual power emitted from the power pack. What I found was that as the current rose, the efficiency actually increased, seen in the data below.
Average Current (A)
0.616
1.206
1.834
2.445
3.046Average Energy Supplied (J)
(P=W/t)
55.
238
653
1349
2356
Average Energy Required (J)
(q=mcT)
140
564
1284
2346
3655
Average Efficiency (%)
(Efficiency = (Energy output/ energy input) x 100)
39
42
50
57
64
Does anybody know why the efficiency would actually increase when the current was raised?
(sorry for the data being spread out, I couldn't find out how to insert a table)
Homework Equations
P=VI
P=I^R
P=W/t
Q=mcT
(Efficiency = (Energy output/ energy input) x 100)
The Attempt at a Solution
The only reason I can think of for the efficiency increasing would be having something to do with how we did not maintain the same voltage throughout the experiemnt, otherwise I'm reeally not sure.
Thanks in advance