High School Physics Transformer Master Advanced .

dBecause the transformer is a kind of dongdong that reduces the current consumption in the transmission process by increasing the output voltage.

And because the ratio of the input to output voltage of the transformer is:

U1:U2=N1:N2 (U1 and U2 are the input and output voltages, and N1 and N2 are the ratio of coil turns).

P loss = U*U r (r is the resistance of the transmission line).

i=u2/r

By increasing the number of turns of the high-voltage coil, U2 can be increased, thereby reducing I and P loss.

The size of r is related to the length, thickness and resistivity of the wire, and the size of r can be reduced by increasing the thickness of the wire.

Therefore, the answer is DA because the current is small.

The current should be large in b.

The current should be small in c.

a, b, c are all wrong.

D is right. Ideal transformer p in = p out.

The input power p=ui input is high voltage u=p i so the current is small.

The output power p=ui output is low voltage u=p i so the current is large.

The ideal transformer should be free of power loss. Therefore, the current in the coil at the high-voltage end must be small, and of course, the number of turns at the high-voltage end is also large, (the number of turns is proportional to the voltage, like). What does the thickness of the wire mean?

The thick wire is subjected to a larger current and has a smaller resistance, while the thin wire is subjected to a smaller current and has a greater resistance. That's all there is to say.

In this question, you did not give the direction of the transformer coil, so you can't judge the level of the CD potential, and the answer should be b or c

First of all, because of the action of the diode, only half of the input is left, just like Figure A.

Secondly, the transformer principle, the alternating voltage at the input end produces a changing magnetic field, and the current is induced at the output end, which is related to the rate of change by Faraday's law of electromagnetic induction, (1) The size problem: the voltage at the input end is the smallest, the rate of change is the largest, and vice versa, so the induced electromotive force is the largest at the beginning. (2) Direction problem:

The input becomes larger and then smaller, and the direction of the output changes.

Finally, according to the direction of the coil, it is judged to be B or C

The function of the rectifier diode is to turn alternating current into direct current. Alternating current is an electric current whose direction changes periodically over time. The reverse of direct current does not change. As you can see from the options, bc. should be excluded

What about Figure B? Send it to my mailbox 1015977397

When the electrical power consumed by the user becomes larger:

Because it is an ideal transformer, U2 does not change.

Because of the existence of the wire resistance, the power is large, the current is also large, and the voltage drop on the resistance R is also large, so U3 becomes smaller.

Because the user consumes a lot of power, the output power of T1 and the input power of T2 will of course also increase, so P2 becomes larger and P3 becomes larger.

When the power consumed by the user increases, the output power of the generator also increases, U1 remains the same, P1 becomes larger, U2 remains the same, P2 becomes larger, U3 remains the same, P3 becomes larger, U4 remains the same, P4 becomes larger, the output voltage of the generator is its inherent characteristic will not change, only the power will change.