Ohm s Law The current in a conductor is directly proportional to the voltage across the conductor an

1. Ohm's law talks about the relationship between the three UIR, and it is necessary to first explain that a certain physical quantity is certain, and then it can be said what is the ratio of another quantity to the third quantity. Sometimes it doesn't say who is certain, but it says what kind of comparison and so on, that's because there is already an implicit condition in the title that a certain physical principle is certain, and you have to find out this implied condition. As said:

The current of this lamp is directly proportional to the voltage at both ends. When it says this lamp, it means that the resistance does not change (regardless of temperature). Another example is "after changing the light bulb,。。

This means that the voltage does not change.

2. Know that it is proportional and inversely proportional, which can be used for calculation (can save some steps), especially when filling in the blanks and selecting without process, it is very easy to use.

3. "XY Happy Bird" is very right, and I will borrow it: mathematically speaking, the three quantities are the same on what premise. But physically, resistance is intrinsic (regardless of temperature), voltage is added by us, and only the current is "passive", and you add voltage to the intrinsic resistance to produce current.

Therefore, when Ohm's law is generally described, it is said that "the current in a conductor is directly proportional to the voltage at both ends of the conductor and inversely proportional to the resistance of the conductor." ”

That is to say, there are only three ways to say what to say: the current is proportional to the voltage...

The current is inversely proportional to the resistance...

Voltage is proportional to resistance...

The order in which it is said is i u r, and it cannot be messed with.

I don't know what to ask about.

In general, resistance is an intrinsic property of a conductor and can be considered a constant.

A voltage source is usually used to analyze a circuit, so that the voltage is the input signal or independent variable, and the current is generated by the voltage added to the circuit, which is the dependent variable or output.

Of course, the resistance of the actual conductor is related to the temperature and the magnitude of the current, and it is not constant, but these can not be considered in secondary school.

1,。First of all, you need to know how Ohm's law is derived. It is proved by experiments that when the voltage is constant, the current through the conductor is inversely proportional to the resistance of the conductor, and when the resistance is constant, the current through the conductor is proportional to the voltage of the conductor.

2 Uses: For example, for a light bulb, we think that its resistance is certain, when the voltage applied to it increases, the current through it increases, that is, it is proportional.

Ohm's law: In the case of () unchanged, the current in the blind body of the guide is inversely proportional to the resistance of the conductor.

a.Resistance. b.Potential.

c.Electrical energy. d.Voltage.

Correct answer: d

According to Eumetan's law, the resistance of the leading plexus is inversely proportional to the current passing through it. （）

a.That's right. b.Mistake.

Correct Answer: a

Ohm's law: In a closed circuit, when the temperature of the conductor is constant, the current through the conductor is proportional to the voltage applied to both ends of the conductor and inversely proportional to the resistance of the conductor.

When it is also proportional to the voltage, the resistance does not change; When inversely proportional to the resistance, the voltage across the conductor is constant.

I don't know what to ask.

Yes, the closed loop is inversely proportional to the same loop.

Ohm's Law. The relationship between the resistance of the conductor, the voltage at both ends of the conductor, and the current flowing through the conductor The resistance value of the conductor is determined by the nature of the conductor itself, and has nothing to do with the voltage at both ends of the conductor and the current flowing through the conductor Therefore, D is selected

(1) According to the content of Ohm's law, it can be seen that the resistance value of the resistance is unchanged for a certain section of conductor, that is, when the resistance is constant, the current in the conductor is proportional to the voltage at both ends of the conductor; When the voltage at both ends of the conductor is constant, the current through the conductor is inversely proportional to the resistance of the conductor It can be seen that option A is correct, option B is incorrect, and option C is correct

2) The voltage at both ends of conductor A and conductor B is greater than the voltage at both ends of conductor B, but the resistance of conductor cannot be determined, so the current through conductor A is not necessarily greater than the current of conductor B, so option D is incorrect

Therefore, C

Actually, the above narrative is two sentences, which should be:

Sentence 1: The current in the conductor is proportional to the voltage at both ends of the conductor.

If the conductor is certain, then r is certain, and according to r=u i, i is proportional to u. It can be seen that the control variable, that is, r is a fixed value.

Second sentence: The current in the conductor is inversely proportional to the resistance.

If the voltage is constant, then you must be certain, and according to i=u r, i is inversely proportional to r. It can be seen from this that the control variable, that is, u is a fixed value.

Because of the laws in physics, the language requires conciseness, so the merging of two sentences into one sentence eliminates some detailed conditions.

i=u r, so i 1 r, i u. Because it can list proportional formulas, it is correct in multiple-choice questions (this reasoning is conventional, so there is no need to dwell on it). In addition, resistance is a property of the conductor itself, so it cannot be said that resistance is directly or inversely proportional to voltage or current.

The magnitude of the resistance depends on its length, temperature, and cross-section.

(1) Ohm's law means that the current passing through the conductor is directly proportional to the voltage at both ends of the conductor and inversely proportional to the resistance of the conductor; The expression is i=ur

2) Ohm's law can also be understood in this way: when the resistance is constant, the current through the conductor is proportional to the voltage at both ends of the conductor; At a certain voltage, the current through the conductor is inversely proportional to the resistance of the conductor

So the answer is: voltage; Resistance. Resistance. Direct ratio; Voltage. Inverse ratio; i=ur．