207
FIGURE 14-1
One type of calorimeter.
Electrical energy is given by
- /coulombs\
energy = (volts)(amperes)(seconds) = (volts)
:— (seconds)
\ seconds /
= Elt = I'
2 Rt volt coulombs (or joules)
By definition,
I joule = I volt coulomb (the Si-approved unit of energy)
I calorie = 4.184 joules (the so-called mechanical equivalent of heat)
By combining these laws and definitions, we get
I
2 Rt
electrical energy =
calories