Heating Water Using Circuit Resistor

[Canadian]

Homework Statement

In a circuit a 20-ohm resistor sits inside 104 g of pure water that is surrounded by insulating Styrofoam, there are additional resistors in the circuit.

If the water is initially at temperature 10.5 degrees celcius, how long will it take for its temperature to rise to 58.5 degrees celcius?
Use 4190 as the heat capacity of water

Homework Equations

V=IR P=VI

The Attempt at a Solution

I assumed that the styrofoam was a "perfect" insulator did not absorb any heat or allow any to escape.

Does this work.

 

[Andrew Mason]

Homework Equations

V=IR P=VI

The Attempt at a Solution

I assumed that the styrofoam was a "perfect" insulator did not absorb any heat or allow any to escape.

Does this work.

Your work and the answer are fine, except that you have too many significant figures in your result.

AM