The heat generated by current passing through a conductor is proportional to the square of current intensity, conductor resistance and energization time, that is, q = i 2rt.
Unit: q: joule j; I: ampere a; R: ohm ω; T: the second second
The pure resistance circuit only contains pure resistance elements, and the electrical W=UIt=Q, U = IR ∴ Q = I 2RT. Note: This relationship only applies to pure resistance circuits. Current does work through a pure resistance circuit, converting electric energy into internal energy and generating heat. Electric power is also called electric heating.
The circuit containing the motor is not a pure resistance circuit. Electric work.
The current does work through the motor, converting some electric energy into internal energy and most of it into mechanical energy.
The motor coil has a resistor R, and the heat generated by current passing through it is not equal to UIt, but only a part of UIt. The reason is that for impure resistors U≠IR and U >: IR.
Question 2: What is Joule's Law? The heat generated when a current passes through a conductor is proportional to the quadratic power of the current, to the resistance of the conductor, and to the electrifying time. The mathematical expression of Joule's Law: Q=I2RT.
Question 3: What is Joule's Law? Joule's law defines that the power generated in the form of heat in a uniform conductor is directly proportional to the product of the resistance of the conductor and the square of the current passing through it. Discipline: electric power (first-class discipline); General theory (two disciplines) Joule's law is a law that quantitatively explains the transformation of electric energy into heat energy by conducting current. The content is: the heat generated by current passing through a conductor is proportional to the quadratic power of current, to the resistance of the conductor, and to the electrifying time. The mathematical expression of Joule's Law: Q = I 2; ×Rt (applicable to all circuits); For pure resistance circuits, it can be deduced that: Q = W = PTq = UIT;; Q = (u 2/r) t1841year. The British physicist Joule found that the heat generated in the current-carrying conductor Q (called Joule heat) is proportional to the square of the current I, the conductor resistance R and the current-carrying time T. This law is called Joule's law. Adopt the international system of units, and its expression is q = I 2; ×Rt or thermal power p = I 2; ×R where the units of q, I, r, t and p are joule (j), ampere (a), ohm (ω), second (s) and watt (w) in turn. Joule's law is an important formula for designing electrical lighting and electric heating equipment and calculating the temperature rise of various electrical equipment. Application of Joule's Law in Series Circuit: In Series Circuit, the currents are equal, so the greater the resistance, the more heat is generated. Application of Joule's Law in Parallel Circuits: In parallel circuits, the voltages are equal. Through the deformation formula, W=Q=Pt=U2/R×t, when U is fixed, the larger R is, the smaller Q is. It should be noted that Joule's law and electric work formula W=UIt are applicable to the calculation of any element and heat generation, that is, Q = W = UIT = Q = I 2 can only be used in circuits similar to electric heaters (pure resistance circuits); Rt =U^2/R×t。 In addition, Joule's law can also be transformed into Q=IRQ (the latter q is the charge in coulomb (c)). Edit this paragraph to correctly understand and use Joule's law. Joule's law is an experimental law and has a wide range of applications. When it comes to the thermal effect of current, for example, it is necessary to calculate the heat released when the current passes through a certain circuit; Joule's law can be used to compare the heat released by a circuit or conductor, that is, to consider the requirements of the circuit from the perspective of current thermal effect. According to the formula of Joule's law, the heat generated by current passing through a conductor is proportional to the square of current intensity, to the resistance of the conductor, and to the electrifying time. If all the work done by current is used to generate heat. That is, W=UIt. According to ohm's law, there is w = I 2; Rt. it should be noted that w = u 2; /Rt and w = i 2; Rt is not Joule's law, they are derived from Ohm's law, and can only be established under the condition that the work done by current completely converts electric energy into heat energy (pure resistance circuit). Such as electric furnace, soldering iron and other electrical appliances, these two formulas are equivalent to Joule's law. When using Joule's law formula, each physical quantity in the formula should correspond to the same conductor or the same circuit, and the corresponding relationship is the same as when using Ohm's law. When several physical quantities appear in the topic, the angle code should be added to show the difference. Note: W=UIt=Pt is applicable to all circuits, while W = I 2; rt=u^2; /Rt is only used for pure resistance circuits (all for heating). Edit the physical experiment method for Joule's Law experiment as shown in the figure, and study the relationship between heat generated by current passing through a conductor and conductor resistance. Because we can't directly observe how much heat is generated by the current, we can indirectly observe it by observing the temperature of the liquid in the bottle (indicated by the thermometer). This method is called transformation. In this experiment, a * * * involves three physical quantities-current, resistance and heat. We only need to study the relationship between heat and resistance, so we should keep the current constant (so we connect the two resistors in series). In order not to affect the results, this method is called the control variable method. [1] Edit the experimental principle of this paragraph. Joule's law is a law that quantitatively explains the transformation of electric energy into heat energy by conducting current. 184 1 year, the British physicist Joule found that the heat q generated in a current-carrying conductor (called Joule heat) is directly proportional to the square of the current I, the resistance r of the conductor and the electrifying time t, which is called Joule's law. Adopt the international system of units, and its expression is q =...> & gt