Work and current capacity

Содержание и основные понятия

The electric field works on charges, and the energy is converted into heat, light, mechanical or chemical energy.
GEF · 10 grade
PIF · Baseline
Interactive model
current
Power
heat action
Source MAP
01
The physical picture
What happens and what boundaries the model has.
Main message
The electric field works on charges, and the energy is converted into heat, light, mechanical or chemical energy.
The power of the element is equal to a product of voltage per current.
In the resistor, electric power is transferred to the inner energy, according to the law of Joel-Lenz.
The source ' s PAC is reduced with increased losses on internal resistance.
How to reason
First, name the system and the interaction, then select the values, and only then write down the law. The formula works within the model's assumptions.
02
Laws and values
Symbols should be read as a relationship of values, not as a recipe for substitution.
A
=
U
I
t
A=UIt
A
=
U
I
t
current
P
=
U
I
=
I
2
R
=
U
2
R
P=UI=I^2R=\frac{U^2}{R}
P
=
U
I
=
I
2
R
=
R
U
2
​
Power
Q
=
I
2
R
t
Q=I^2Rt
Q
=
I
2
Rt
Joul-Lenz
Review of the situation
If the current is doubled through the same resistor, the thermal power is quadrupled.
04
Links and application
In the real world
If the current is doubled through the same resistor, the thermal power is quadrupled.
Model verification
Compare the prediction with observation, evaluate the units, the order of magnitude and the influence of the factors not taken into account. Disparity does not always mean an error of law: often idealization is no longer sufficient.
C
What needs to be understood
Outcome 1
Explain the physical meaning of the topic "Work and current power" through the model, not just the formula.
Outcome 2
Clear and correctly use terms: current, power, thermal action.
Outcome 3
Indicate the conditions for the applicability of the law, verify units and limit cases.
T
Terms of the topic
The definition should indicate the physical meaning, not a substitute for a domestic synonym.
current
Power transmitted by the electric charge field and converted along the circuit.
Power
Work or energy transferred per unit of time.
heat action
Increase the internal energy of the conductor while passing the electric current.
Source MAP
Ratio of external circuit power to full source power.
F
Origin and conclusion of the formulas
The fundamental law cannot be "proven" by algebras: for each record, it is stated whether it is a definition, an experimental law, or a model effect.
A
=
U
I
t
A=UIt
A
=
U
I
t
model effect
It's the current.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
A
=
U
q
A=Uq
A
=
U
q
The voltage is defined as the operation of the electric field per unit of transferred charge.
I
=
q
t
⇒
q
=
I
t
I=\frac{q}{t}\quad\Rightarrow\quad q=It
I
=
t
q
​
⇒
q
=
I
t
At constant current during time t, the section passes through the charge It.
A
=
U
I
t
A=UIt
A
=
U
I
t
Setting the transferred charge into the expression of the work gives the formula.
Conditions:
The constant voltage U and current I at the interval t; A is the energy transmitted to the selected section of the circuit. The variable values require an integral UI dt.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
P
=
U
I
=
I
2
R
=
U
2
R
P=UI=I^2R=\frac{U^2}{R}
P
=
U
I
=
I
2
R
=
R
U
2
​
model effect
Power.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
P
=
A
t
,
A
=
U
I
t
⇒
P
=
U
I
P=\frac{A}{t},\quad A=UIt\quad\Rightarrow\quad P=UI
P
=
t
A
​
,
A
=
U
I
t
⇒
P
=
U
I
The power is equal to work per unit of time, so for constant current, it's UI.
U
=
I
R
⇒
P
=
I
(
I
R
)
=
I
2
R
U=IR\quad\Rightarrow\quad P=I(IR)=I^2R
U
=
I
R
⇒
P
=
I
(
I
R
)
=
I
2
R
The adjustment of Oma's law expresses power through current and resistance.
I
=
U
R
⇒
P
=
U
U
R
=
U
2
R
I=\frac{U}{R}\quad\Rightarrow\quad P=U\frac{U}{R}=\frac{U^2}{R}
I
=
R
U
​
⇒
P
=
U
R
U
​
=
R
U
2
​
Another setup expresses the same power over voltage.
Conditions:
Permanent current in omic area with constant resistance to R; equations I2R and U2/R are not applicable to neo-matic elements without regime specification.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
Q
=
I
2
R
t
Q=I^2Rt
Q
=
I
2
Rt
empirical law
Joul Rlenz.
The following is an indication of the definition, experience or law from which this entry arises and where it is applicable.
Q
=
A
эл
Q=A_{\mathrm{эл}}
Q
=
A
El.
​
In a stationary resistor, electrical work is transferred to internal energy and released as heat; this is consistent with measurements.
A
эл
=
U
I
t
A_{\mathrm{эл}}=UIt
A
El.
​
=
U
I
t
The constant current on the site is UIt.
U
=
I
R
⇒
Q
=
I
2
R
t
U=IR\quad\Rightarrow\quad Q=I^2Rt
U
=
I
R
⇒
Q
=
I
2
Rt
For an ome conductor, the Oma Act translates the experimental law into the said form.
Conditions:
Fixed omestic conductor, constant I and R, all electrical energy becomes heat in the conductor; there is no visible other work or energy accumulation.
Monitoring:
The dimensions of both parts shall coincide; the result shall be checked for sign, order and limit case.
!
Model boundaries and typical errors
Error: Forget model condition
You can't change the formula to any situation just because the letters match. The key condition of this topic is that the power of the element is equal to a work of current voltage.
How to Check the Mind
In the resistor, the electrical energy is transferred to the inner energy in the law of Joel-Lenz, then check the units, the direction of the vectors and the behaviour of the result at zero or very large parameter.
Σ
Conclusion on the topic
Work and current capacity
The electric field works on charges, and the energy is converted into heat, light, mechanical or chemical energy.
The power of the element is equal to a product of voltage per current.
In the resistor, electric power is transferred to the inner energy, according to the law of Joel-Lenz.
Any numerical result shall be accompanied by a unit, a sign and an explanation of its physical meaning.
The content is consistent with the FRP on Physics of the OS/OSS 2025 and the subject matter of the current lines of the PNP: I. M. Peryškin and co-authors (7–9), G. J. Mäkishev and coauthors (10–11), and with the lines "Engineers of the Future" and V. A. Kasyanov. The original texts are not reproduced, the text of the textbooks is not reproduced.