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The basic problem of the voltage of the parallel circuit in junior high school physics, physics teacher, please come in, there is an additional is not to say 'the voltage at both ends of each parallel branch in the parallel circuit is equal' Junior three physics parallel circuit voltage basic problem, physics teacher please come in, there are additional It doesn't mean that the voltage at both ends of each parallel branch in a parallel circuit is equal, but why is it equal to the total voltage at both ends of the main circuit? It doesn't mean that the two outgoing branches are equal, but it has to be smaller than the main circuit, just like 2 can't be equal to 2 + 2
The sentence "the voltage at both ends of each parallel branch in parallel circuit is equal" is right and does not need any conditions. But "equal to trunk circuit" does not hold at all times. It only holds when the parallel circuit is directly connected to both ends of the battery (that is, the simplest parallel circuit)
Circuit composition: power switch (closed) wire motor ammeter (measure motor voltage)
Known: the current through the motor measured by the ammeter is I, the motor resistance is r, and the power on time is t
Then q equals the square of I times r times t
Q = I & # 178; RT is correct
Joule theorem formula,
If the motor circuit is not a pure resistance circuit, then q ≠ W, w = uit
When the voltage at both ends of a section of conductor is 2V, the current in the conductor is 0.2A. If the voltage increases to 9V, what is the current in the conductor?
R = u1i1 = 2v0.2a = 10 Ω I2 = u2r = 9v10 Ω = 0.9A answer: when the voltage increases to 9V, the current in the conductor becomes 0.9A
RELATED INFORMATIONS
- 1. When the voltage at both ends of a conductor is 8V, the current passing through it is 0.2A. When the voltage at both ends of a conductor decreases by 2V, how much is the current passing through it and how much is its resistance?
- 2. The voltage at both ends of the wire is 10V, and the resistance of the wire is ignored. Calculate the current in the wire
- 3. There is a resistance line. If the current in the resistance line is 0.5A when 6V voltage is applied at both ends, the resistance of the resistance line is______ Ω, if the voltage of 12V is applied at both ends, the current passing through the resistance line is______ A. The resistance of the resistance wire is______ Ω; if there is no voltage at both ends of the resistance line, the current through the resistance line is______ A. The resistance of the resistance wire is______ Ω．
- 4. When a voltage of 6V is applied at both ends of a conductor, the current passing through it is 0.4A, and the resistance of the conductor is__ If the voltage at both ends of the conductor becomes 9V, the resistance of the conductor is__ The current through the conductor is__ .
- 5. As shown in the figure, two parallel long and straight wires are respectively connected with current I1 and I2 in opposite directions, and I1
- 6. Explain: why is the potential equal at both ends of a wire connection in a circuit?
- 7. As shown in the figure, two parallel long straight wires a and B carry currents of the same size and opposite direction, and the magnetic force on a is F1. When a uniform magnetic field perpendicular to the plane of the wire is added, the magnetic force on a becomes F2, and the magnetic force on B becomes () A. F2B. F1-F2C. F1+F2D. 2F1-F2
- 8. How to use a wire and a battery to light a small bulb? It's a primary school version
- 9. When two conductors with the same length and different cross-sectional area are connected in series, they compare the current and voltage. The thin one is ab, and the thick one is BC
- 10. Is there any relationship between the current and the cross-section of the wire? If the material is the same and the length is the same, only the cross-sectional area is different I = nesv
- 11. In physics calculation, the voltage of power supply in series circuit remains unchanged, which means that the voltage is equal everywhere? Is the voltage equal everywhere equal to the supply voltage
- 12. The voltage at both ends of the conductor is 12 volts. The current passes through the conductor in 5 seconds and does 24 joules of work. During this period, the current passes through the cross section of the conductor
- 13. In 5 minutes, if the electric quantity passing through the cross-sectional area of a conductor is 60C, the current passing through the conductor is 60C How much is it There are 20 identical lamps connected in series to a 200V circuit. The current at both ends of each lamp is A .4840V B.10V C.200V D.0.1V
- 14. If 50V voltage is applied at both ends of the resistance, and 20c electric quantity of the resistance passes through the cross section within 10 seconds, the resistance value of the resistance is______ Ω．
- 15. When the voltage at both ends of a resistor increases from 3V to 4V, the current through it increases by 1a, and then the current in the conductor is? A
- 16. Resistance R1 = 7 Ω, R2 = 5 Ω, connected in series at both ends of 12V power supply. At this time, the total resistance of the circuit is_____ Ω, R2 voltage___ 5. In parallel in a 3V circuit, The total resistance after parallel connection is____ Ω, when the current passes through the main road____ A. Comparison of current in R1 and R2____ . [a total of 5 blanks, yes, fill in the blanks = 3 =, no process, no matter]
- 17. In the circuit shown, given resistance R1 = 4 Ω, R2 = 8 Ω, R3 = 6 Ω, R4 = 12 Ω, voltage US1 = 1.2V, US2 = 3V, use superposition theorem to calculate current I
- 18. When the voltage applied at both ends of a resistor is 5V, the current passing through it is 0.5A. To make the current passing through the resistor 1a, add it to both ends of the resistor What is the voltage applied at both ends of the resistor? If the voltage at both ends increases to 20V, what is the resistance of the resistor? What is the current passing through it?
- 19. When the voltage applied at both ends of a resistor is 5V, the current passing through it is 0.5A. To make the current passing through the resistor 1a, add it to both ends of the resistor What is the voltage applied at both ends of the resistor? If the voltage at both ends increases to 20V, what is the resistance of the resistor? What is the current passing through it?
- 20. Metal conduction refers to the directional movement of free electrons in the metal under voltage, but after the electrons in a power supply, a light bulb and a wire move Where does the electron go to the negative pole? Is there a new electron supplement or is the nucleus charged after the electron is removed