In the first semester of the second year of high school, physics is explained, and in the second yea

When the sliding rheostat is moved to the far right, the ammeter shorts R2, and the small bulb in the circuit is connected in parallel with R3 and then in series with R1.

The resistance of the small bulb r = u forehead 2 p amount = 9 r and = 6 * 10 (6 + 10) =

The power supply electromotive force e=ir and +ir1+ir=1*

When the sliding rheostat is moved to the far left, the small bulb is shorted by the wire. At this point, R2 is short-circuited by the ammeter. Only R1 is connected to the circuit in the circuit. At this point i=e (r1+r)=

When the sliding vane P is placed in a certain position, the power is maximum, and the left end of the sliding rheostat is connected in parallel with the small bulb, and the right end is connected in series with R2, but it is short-circuited by the ammeter. In this case, both R1 and the internal resistance are regarded as the internal resistance of the power supply.

Then there is r and = r1+r=3 r and = r*6 (r+6)=3 and the solution is r=6

When the resistance at the left end of the sliding rheostat is r=6, the electrical power is maximum.

In this case, the trunk current i = the current of the sliding rheostat = i 2i and then use p = i2*r to calculate the power of the sliding rheostat.

Hello, glad to answer for you!

If you need a detailed explanation, please ask questions, you will be happy when you have heard it, and it is not easy to hope for answers!

Satan is going crazy, and the activity begins, and the neighbors come up and send it.

Choose C. You don't care about the nature of the circuit, just analyze it normally.

Did you learn about capacitors? It is just two parallel plates, and there is nothing in between, which is equivalent to an open circuit.

There is a capacitor on the left side of the voltmeter, open circuit, there is no voltage, and the number is 0

Although the voltmeter is often regarded as an open circuit, you must be clear about how it works. It's not that there is no current passing through the voltmeter, but its resistance is too large, and the current can be approximated as 0, but it is not actually 0

In other words, although the electrometer is connected to the voltmeter on the right, the right side is the path. The left and right are connected, which is equivalent to the power supply being directly connected to the electrometer, so the indication is 200, that is, the power supply voltage.

Answer: The capacitor is selected C, which can be understood as the two conductor plates are not in contact with each other, so the capacitor is open. When energized, one piece has a + on it and the other has a -, so to balance, the capacitor will be discharged. Similar to rechargeable batteries.

The capacitor acts as an open circuit, so the voltmeter becomes a wire and the electrometer measures the supply voltage. Therefore, the answer should be A

If it's hard for you to understand, it can be understood as: eddy currents are microscopic forms of directional currents.

I believe you understand how the magnetic field is obtained from the perspective of onlookers: the orderly arrangement of electric charges.

There is a condition for the formation of electric current: the circuit is closed. But the whole disk is a solid body, with a three-dimensional shape of thickness, i.e. it can form a closed circuit in itself.

For example, the "wires" on the copper plate and the "wires" on the ground form a closed path. This microscopic specific industry current is the eddy current.

If all the small eddy currents are arranged in an orderly manner, a macroscopic current is formed.

You can think of it this way: as long as the current generated by using its own structure can be considered eddy current.

Key point: Orderly arrangement. Hope it helps you somewhat.

When balancing position:

n=mgk(lo-l)=mg

Anywhere:

f-sum = mg-n'

mg-k(lo-l')

k(lo-l)-k(lo-l')

kl'-kl

k(l'-l)

Considering the relationship between displacement and resultant force direction, kx can be found to have a vibration that satisfies f=-kx, which is proved.

This problem should be an internal resistance to confuse people, the potential difference is the voltage, one thing, but to be strictly distinguished from the electromotive force, here, let us find the potential difference is the voltage refers to the road end voltage, because R1 and R2 are in parallel, the voltage is equal, then the road end voltage is equal to their voltage. If according to the understanding of junior high school, the power supply has no internal resistance, at this time, only the power supply voltage is equal to the potential difference between the two points of AB, but we have to consider the internal resistance of the conductor rod R, which is equivalent to the internal resistance of the power supply, which belongs to the internal circuit, except for the internal power supply, the others are external circuits, the internal resistance of the power supply is always connected in series with the resistance of the external circuit, and the power supply electromotive force is equivalent to the total voltage of the entire circuit, which is equal to BLV, and the total voltage of this point can be calculated by assigning this total voltage to different electrical appliances in the circuit. Let's calculate the potential difference according to the law of partial voltage, the external circuit is two resistors in parallel, their total resistance R1R2 (R1+R2), for the time being, set this string as R, the internal resistance of the power supply R, the two parts of the resistance distribute the electromotive force, RBLV (R+R).

AB slides along the guide rail to cut the magnetic inductance line movement, and the induced electromotive force e=blv "1".

The resistors R1 and R2 on both sides are the parallel resistors of the external circuit, and the resistance value R=R1*R2 (R1+R2) 《2》

AB is equivalent to a power supply with an internal resistance of R and an electromotive force of E, and the potential difference between the two points of A and B is the equivalent end-of-circuit voltage of the closed circuit

uab=e-i*r 《3》 i=e/(r+r) 《4》

Lianli solution.

Isn't that simple.

AB rod is moving at a constant speed, E=BLV, E is a fixed value, then it is studied as a constant power supply, and the magnetic field is directly removed, AB is a battery. Then this translates into asking you to find the voltage of the external circuit, and the Ohm's law of the closed circuit is not just set directly?

There are three principles for this kind of topic: three balls with the same line, two large clamps are small, and two are different from the same clips.

1) C is negatively charged.

Balance the force on c.

Balance of forces on a.

q=4q/9

c Capacitor For direct current, it is equivalent to an open circuit after the positive and negative poles are fully charged.

Our voltmeter is a big resistance in this circuit, relative to the capacitor, so the capacitor connected in parallel with the voltmeter can be directly removed, and the circuit properties remain unchanged.

The electrometer has similar properties to capacitance, and it is equivalent to an open circuit after being fully charged. Therefore, the voltage measured by the electrometer is actually the power supply.

This circuit has no current because it has a capacitor, and the capacitor is a straight through cross, so U'=200v

However, the electrometer connected to C cannot measure the voltage of the circuit, so u=0V

Answer: BC Analysis:

This title is Pebi electromagnetic drive, the direction of the force can be judged by Lenz's law, and then the motion can be judged by Newton's second law When the magnet passes horizontally through the solenoid, an induced current will be generated in the tube, and the interaction force generated by the extended meaning of Lenz's law hinders the movement of the magnet In the same way, when the magnet passes out, the interaction force generated by the extended meaning of Lenz's law hinders the motion of the magnet, so the magnet decelerates during the whole process, and option b is correct

And for the solenoid on the trolley, in this process, the ampere force of the solenoid is horizontal to the right, and this ampere force makes the trolley move to the right, and has been doing acceleration motion, c pair

(1) The metal rod is used as the research object, and the gravity g=mg=3nAmpere force fa direction is horizontal to the right, support force fn

Equilibrium conditions according to common point forces.

fa=gtan60°=3√3n

fa=bil

b=√3t(2)fn=2g=6n

by Newton's third law.

fn'=-fn=6n

Direction: Vertical rails downward.