For conductors with large resistance, the resistivity must be large or small

Not necessarily, under other conditions (length and thickness are the same), the resistivity is larger.

Not necessarily, resistance = resistivity, length, cross-sectional area, other conditions will also be affected.

Different materials have different resistivity, which is the property of the material itself, the resistivity of copper is less than that of iron, but the resistance of copper can also be greater than that of iron. The magnitude of the resistance is related to the resistivity, length, cross-sectional area.

When the length, cross-sectional area, and temperature (as if the previous few did not mention this), the resistivity is proportional to the resistance. In addition: "The resistivity of almost all metals varies linearly with temperature, i.e. = o(1+at)."

where t is the temperature in Celsius, o is the resistivity at o, and a is the temperature coefficient of resistivity. The encyclopedia mentions it (the effect of temperature) in the text 1 2 and must say at what temperature the resistivity of a certain conductor is.

Resistivity is a property of matter, and it is the same as density.

Your question seems to be asking, "Is the density of an object with a large mass greater or smaller?" ”

You can take a closer look at the meaning of resistivity in the encyclopedia, and you will understand.

Resistivity depends on the properties of the object, resistance = resistivity * length cross-sectional area. With the same length, cross-sectional area, the resistance is proportional to the resistivity.

To understand resistance, the following questions need to be clarified:

How did the concept of resistors come about?

It has been discovered that conductors not only conduct electricity, but also hinder current while conducting electricity. The most convincing experiment is that the current through different conductors is generally different at the same voltage.

In order to express the magnitude of the resistance of a conductor to an electric current, it was introduced in physicsResistanceThis physical quantity.

Definition: Resistance r=u i

Observe the ammeter with a different fixed resistance.

Indication number. The magnitude of the conductor's resistance is the nature of the conductor itself, and has nothing to do with the magnitude of the voltage u at both ends of it and the current i passing through it. What does it have to do with it?

with the length of the conductor l, the cross-sectional area of the conductor s, the resistivity of the conductor material.

Related – r= l s. ( l, s is certain, the size of the conductor resistance is certain.) ）

Although the magnitude of the resistor is defined in terms of u i, it has nothing to do with whether the conductor is connected to the circuit or not, and the voltage u at both ends of the conductor. Just as the density of matter is defined = m v, the defined quantity is independent of the chosen size of m and v.

Proper understanding of Ohm's law.

i=u/r。The magnitude of the current passing through the conductor is determined by both the voltage u at both ends of the conductor and the resistance r of the conductor. The derived r=u i can be used to calculate the magnitude of the resistor, but the correspondence between u, i, and r should be taken into account.

For example: in a series circuit.

The current passing through two conductors with different resistances is the same, and it cannot be said that "in a series circuit, each cell has the same effect on the current resistance" because in a series circuit, the voltage shared by the resistor is also large.

Resistance is the obstruction of the conductor to the current, it is the property of the conductor itself, related to the material, length, cross-sectional area, temperature, is not affected by the current, voltage Therefore, the answer is: obstruction; Hinder; Big; Material; Length; cross-sectional area; Temperature

This statement is not correct, resistance is a property of the conductor itself, its size is determined by the length of the conductor's material and cross-sectional area, and is also affected by temperature, independent of the voltage applied at both ends of the conductor and the current passing through it.

In general, resistance is an intrinsic physical property of a circuit (or a part).

Therefore, it is generally believed that the higher the voltage applied to the resistor, the greater the current flowing through the resistor.

By Ohm's law, of course.

It is known that the relationship between the voltage applied at both ends of the resistor, the magnitude of the resistance and the magnitude of the current flowing through the resistor is: the magnitude of the current flowing = the resistance value of the voltage at both ends of the resistor; Therefore, when the voltage at both ends of the resistor is constant, the current flowing through the resistor is inversely proportional to the resistance value of the resistance (the resistance increases and the current decreases); When the resistance value is constant, the current flowing through the resistance is proportional to the voltage applied at both ends of the resistance (the voltage increases, the current increases); When the current flowing through the resistor is constant, the greater the resistance value, the higher the voltage applied to the resistor (the voltage is proportional to the resistance value).

When the voltage is constant, the current in the conductor is inversely proportional to the resistance of the conductor, and the greater the resistance, the smaller the current; When the current is constant, the voltage in the conductor is proportional to the resistance of the conductor, and the greater the resistance, the greater the voltage. At a certain resistance, the current in the conductor is proportional to the voltage across the conductor.

The resistance of a conductor to an electric current is called the resistance of the conductor. Resistance is a physical quantity.

In physics, it is expressed as the magnitude of the effect of a conductor on the resistance of an electric current. The greater the resistance of a conductor, the greater the resistance of the conductor to the current. Different conductors, the resistance is generally different, and resistance is a property of the conductor itself.

The resistance of a conductor is usually represented by the letter r, and the unit of resistance is ohm, or short as .

Resistance is a physical quantity that describes the electrical conductivity of a conductor and is denoted by R. The resistance is defined by the ratio of the voltage u at both ends of the conductor to the current i through the conductor, i.e., r=u i, so when the voltage at both ends of the conductor is constant, the greater the resistance, the smaller the current passing through; Conversely, the smaller the resistance, the greater the current that will pass through.

Therefore, the size of the resistor can be used to measure the strength of the conductor's resistance to the current, that is, the conductivity. The amount of resistance is related to factors such as the material, shape, and volume of the conductor, as well as the surrounding environment.

Not to empty books or gestures.

According to i = u r, when the voltage u is constant, the greater the resistance r, the smaller the current i.

All conductor resistances, according to the formula: r = l s, at the same length, the smaller the cross-sectional area, the greater its resistance? Ask for more details!

You can think of the conductor "copper wire" as a "water pipe": 1. The water pipe used by your family to supply water may be 20mm in diameter, and the water supply is very smooth, we say that the water pipe has little resistance to the water; 2. If you replace this water pipe with a diameter of 2mm, you will find that there is not enough water. 3. We say:

The cross-sectional area of the water pipe becomes smaller, so the resistance to the water becomes greater. 4. The resistance of the conductor wire is the same as the resistance of the water pipe to the water, and the smaller the cross-sectional area s, the greater their resistance value. 5. The longer the wire l and the longer the water pipe, the greater the resistance.

6. The current is not visible, but the water flow is visible, which is more intuitive and easy to understand. 7. Others: voltage and water pressure, potential and water level, current and water flow, all have many similarities in the principle of the situation, which can be learned by reference.

**Factors that affect the magnitude of a conductor's resistance.

The magnitude of the resistance is related to the length of the conductor, the cross-sectional area, the material.

Big, small. The resistance of the conductor is related to its length, material, cross-sectional area and temperature, and the resistance of the conductor is related to the length in the case of the same material and cross-sectional area, and the longer the length, the greater the resistance; In the case of the same material and length, the resistance of the conductor is related to the cross-sectional area, and the larger the cross-sectional area, the smaller the resistance.

Resistivity describes the parameters of the conductivity of a Divine Ruler conductor. For a cylindrical homogeneous conductor made of a certain material, its resistance r is proportional to the free length l and inversely proportional to the cross-sectional area s, i.e., r = l s.

The resistivity of a conductor with a large resistance must be large (shouting Huai Tomato).

a.That's right. b.Mistake.

Correct answer to Zheng Cha's case: b

The smaller. What factors are related to the resistance of a conductor.

The resistance of a conductor is related to four factors: conductor material, length, cross-sectional area, and temperature. The resistance of some substances will drop to zero under certain temperature conditions, this phenomenon is called superconductivity, and this kind of conductor is called superconductor.

**Factors that affect the magnitude of a conductor's resistance.

1.When the material and cross-sectional area of the conductor are the same, the longer the conductor, the greater the resistance.

2.When the material and length of the conductor are the same, the smaller the conductor cross-sectional area, the greater the resistance.

3.The resistance of a conductor is related to the material of the conductor.

4.As the temperature increases, the resistance of the metal conductor increases, and when the temperature decreases, the resistance of the metal conductor decreases.

The magnitude of the resistance of a metal conductor is related to four factors: resistivity, length, cross-sectional area, and temperature of the conductor.

According to the law of resistance r= l s

1. The greater the resistivity, the larger the length, the smaller the cross-sectional area, the greater the resistance of the conductor, the higher the temperature increases, the resistivity of the metal conductor increases, and the resistance increases.

2. When the temperature of the conductor drops to a certain temperature, the resistance of the conductor suddenly drops to 0, which is called superconductivity.

3. Thermistile resistance to semiconductors: When the semiconductor is heated, the resistance decreases rapidly with the increase of temperature, and it responds quickly to small temperature changes with high accuracy.