The discussion revolves around calculating the time required for an electric immersion water heater rated at 400 W to heat one liter of water from 10°C to 30°C. The problem involves concepts from thermodynamics and electrical power.
Some participants express confusion regarding the connection between the power of the heater and the heat required to raise the water's temperature. There is an acknowledgment of the need to clarify unit conversions and the calorimetric equation, but no consensus has been reached on a solution approach.
Participants note that the formulas related to voltage, current, and resistance may not be applicable to this problem due to missing information. There is also a misunderstanding about the mass of water in a liter, with one participant incorrectly stating it as 100 grams instead of 1000 grams.
Work out the units. What is a watt? How many grams of water are in 1 liter?rgold said:Homework Statement
The mechanical equivalent of heat is 1cal=4.18J. The specific heat of water is 1cal/g*K and its mass is 1g/cm^3. an electric immersion water heater rated at 400 W should heat a liter of water from 10C to 30C in about how much time
Homework Equations
R=v/i
power=v*i
The Attempt at a Solution
I know the answer is 3.5 minutes but i do not know how to get there. I am pretty lost.[/B]
SteamKing said:Work out the units. What is a watt? How many grams of water are in 1 liter?
BTW, the formulas in Section 2 won't help you with this problem, since you don't know voltage, current, or resistance.
you should calculate amount of heat required to raise the water from t1 to t2 given -then calculate the time taken by the heater to provide that heat-rgold said:The mechanical equivalent of heat is 1cal=4.18J. The specific heat of water is 1cal/g*K and its mass is 1g/cm^3. an electric immersion water heater rated at 400 W should heat a liter of water from 10C to 30C in about how much time
Homework Equations
R=v/i
power=v*i
rgold said:im still confused i know that a watt is joules per second and that 100 grams of water in a liter but how do i connect everything?