Resistance and Power Dissipation Flashcards
1
Q
what is resistance defined as
A
R = V / I
2
Q
what are the units for R V and I
A
- R = resistance, ohms
- V = potential difference, volts, V
- I = current, amperes, A
3
Q
what is the first equation for electrical power
A
P= IV
4
Q
how would you modify the equation if you wanted to find power but you only had the current and resistance
A
- P = IV
- V = IR
- P = I(IR)
- P = I^2R
5
Q
how would you modify that new equation to find power if you only had pd and resistance
A
- P = I^2R
- I = V / R
- P = (V / R) x (V / R) x (R / 1)
- P = V^2R / R^2
- P = V^2 / R
6
Q
what is internal energy
A
the sum of the potential energy and the kinetic energy of the molecules of a body
7
Q
how does the internal energy of a resistor like a filament lamp change as a current flows through it
A
- the electrical energy of the electrons is transferred to the random kinetic energy stores and potential energy stores of the atoms (ions) of the filament
- this increases its internal energy
