Heating metal with resistors

Feb 2018
i'm doing a experiment with thermal contact conductance with cirten configurations of materials and interstitial materials.
Before proceeding to the experimental part of my project i must calculate the necessary power consumpion in order to heat up the material with sufficient rate and end temp. in order to select the right resistance and electrical components.

My calculations so far:

Q= m*c*deltaT [J]
Q-dot= m*c*(dT/dt) [J/s=W]

If I then want to relate this to the electric part of the problem, I have electrical power source were I want to output U=15V, i have set up the formulas as following:

P=(U^2)/R --> R=(U^2)/P R [ohm]

..this all seems to simple, or am i correct in my calculation? (been a while since i last studied these subjects and i haven't got my literature at my currnet location)

Much appreciated/ Victor