My point of view on closed circuits in electricity, seeking identification

That's a mistake! Resistance is the blocking effect of electric current. The greater the resistance, the greater the hindrance, and the greater the difficulty of the directional movement of free electrons.

The high resistance does not mean that there are few free electrons, but that it is difficult to move directionally, and the strength of the electric field required for it to produce directional movement must be large.

In a closed circuit, there are two resistors connected, R1 is greater than R2, because the resistance of R1 is large, if you want free electrons to move directionally (because the current of the series circuit is the same), the electric field strength required by R1 is large, that is, the voltage distributed on R1 is large.

This point of view is not right, the free electrons of metals are a lot, there is not much of a problem, it should be a large resistance to the effect of the resistance, so the current is down.

It can be understood that you are walking in **dense streets and unmanned streets, which is faster.

If R1 and R2 are in series, then the amount of charge passing through any cross-section of the two resistors is equal at the same time (because the currents are equal), so the number of free electrons passing through either cross-section is also equal at the same time.

If R1 and R2 are connected in parallel, similar reasoning can be made.

Note:1The current is formed by the directional movement of the charge, and the irregular movement of the charge cannot form the current;

2.The directional movement of free electrons through a certain cross-section is somewhat dependent on the magnitude of the current and the time of energizing. （q=it）

In this problem, Ohm's law is used to analyze r=u i, and consider that the power supply has internal resistance a, the power supply is short-circuited, but there is internal resistance, and the current will not be infinite.

b, open circuit is that the terminal voltage is equal to the supply voltage.

c, the greater the resistance, the smaller the current.

d, let the internal resistance be r, the external resistance is r, then the current i=u (r+r), the terminal voltage u2=r*u (r+r)=u (1+r r), so the larger r, the greater the road-end voltage.

A, false. When the power supply is short-circuited, the input current is short-circuit current.

b False. When the power supply is disconnected, the end-of-circuit voltage is equal to the supply voltage.

c False. The greater the resistance of the external circuit, the greater the output voltage.

d Right. The greater the resistance of the external circuit, the greater the voltage at the end of the road.

a When the power supply is short-circuited, the output current is infinite.

Let the power supply voltage be U, the internal resistance is R, and the external resistance is R, then the current in the circuit i= (r+r)=u r total, when the external resistance is zero, the current i=u r, the current is very large, but not infinite, A is wrong. When the power supply is broken, because the current is zero, the voltage at both ends of the internal resistance is zero, and the voltage at the end of the circuit is the power supply voltage, B is wrong. c The greater the resistance of the external circuit, the total output current is by i= (r+r)=u r, and the smaller the output current, so c is wrong.

d The greater the resistance of the external circuit, the smaller the output current, the smaller the voltage at both ends of the internal resistance U=i r, and the greater the voltage at the end of the circuit = U total -U, so D is right.

Answer D analysis: The load of the power supply increases, it may be that the number of electrical appliances incorporated increases, and the more the external resistance is smaller, and the smaller the road-end voltage, so D is wrong

a. According to Ohm's law of closed circuits i=e

r+r, it can be seen that the current in the closed circuit is proportional to the electromotive force of the power supply, and inversely proportional to the resistance of the whole circuit, so a is correct

B. When the external circuit is disconnected, the current in the circuit is zero and the internal voltage is zero, then the terminal voltage is equal to the electromotive force, so B is wrong

c. The power supply electromotive force is equal to the voltage between the two poles when the power supply is not connected to the circuit, and when the power supply is connected to the circuit, the power supply electromotive force is greater than the voltage between the two poles of the power supply, so c is wrong

d. When the external resistance increases, the current in the circuit decreases, the internal voltage decreases, and the road-end voltage increases, so D is correct

Hence the choice: AD

The proportions in physics must control the variables

1: Ohm's law of closed and vertical circuits is that the current in the closed circuit is proportional to the electromotive force of the power supply,—— variable: when the sum of the internal and external resistance is absolutely overwhelming (when it is constant)!

2. Ohm's law of loose fiber attitude closed circuit is that the current in the closed circuit is inversely proportional to the sum of the internal and external resistances ,—— variable.

When the electromotive force of the power supply is constant (when it does not change)!

a. According to Ohm's law of closed circuits, the current in the closed circuit is directly proportional to the electromotive force of the power supply and inversely proportional to the resistance of the whole circuit, so a is correct

B. When the external circuit is disconnected, the current is zero, the internal voltage is zero, and the road-end voltage is equal to the electromotive force, so B is wrong

c. When the external circuit is short-circuited, the external resistance is close to zero, and the current in the circuit is i e according to Ohm's law of the closed circuit

r Therefore b is correct

D. When the external resistance increases, the current decreases, the internal voltage decreases, and the road-end voltage increases

Answer: When the external resistance of D increases, the total current in the circuit decreases, the internal voltage decreases, and the voltage at the end of the circuit increases, so option D is wrong.

The proportions in physics must control the variables

1: Ohm's law of closed circuits is that the current in the closed circuit is proportional to the electromotive force of the power supply,—— variable: the sum of internal and external resistance is a certain time (when it is constant)!

2. Ohm's law of closed circuits is that the current in a closed circuit is inversely proportional to the sum of internal and external resistance,—— variable: the electromotive force of the power supply is constant (when it is constant)!

Regardless of the conditions, the voltage divided by the current is a resistance, and external factors such as your temperature can only change the coefficient k