The circuit diagram of the relationship between current, voltage and resistance is as follows:
The relationship between resistance, voltage and current is Ohm's law I=U. /R, or U=IR. Expressed in words, in the same circuit, when the resistance is constant, the current flowing in the conductor is proportional to the voltage across the conductor; when the voltage across the conductor is constant, the current flowing in the conductor is inversely proportional to the voltage across the conductor; resistance of the conductor.
In physics, resistance represents the resistance of a conductor to current flow. The greater the resistance of a conductor, the greater the conductor's resistance to current flow. Different conductors generally have different resistances. Resistance is a property of the conductor itself.
Factors affecting resistance:
1. Length: when the materialau and cross section are the same, the longer the length of the conductor, the greater the resistance.
2. Cross-sectional area: When the material and length are the same, the smaller the cross-sectional area of the conductor, the greater the resistance.
3. Material: When the length and cross section are the same, the resistance of conductors of different materials is different.
4. Temperature: For most conductors, the higher the temperature, the greater the resistance, as with metals; for some conductors, the higher the temperature, the lower the resistance, like carbon.
Resistance is a property of the conductor itself, so the resistance of the conductor has nothing to do with whether the conductor is connected to the circuit, if there is current in the conductor , current size, and other factors. The resistivity of a superconductorr is zero, so the resistance of a superconductor is zero.
Which of the following images correctly reflects the relationship between physical quantities ( ) A. The relationship between the water pressure at a certain point inside and the depth B . Electricity is produced when electric current passes through conductors.
Electricity originally existed in nature. Later, people gradually studied and were finally able to generate electricity themselves.
Electricity is produced by an electromagnetic induction generator using magnets and coils, which was researched and invented by Faraday.
Electricity used today can be roughly divided into electricity generated by generators and electricity converted from chemical energy (such as batteries). In addition, electricity is also produced from sunlight, and other methods of producing electricityelectricity are still under development. ?
Of course, the electricity used in homes is produced by generators. ?
Now let’s talk about the principles of electricity generation! ?
To produce electricity, you need magnets and coils that generate electricity. ?
Magnets have a magnetic force that attracts iron and other metals. The range reached by this force is called the magnetic field. ?
Move the coil in this magnetic field and the coil will generate electricity. However, in a strong magnetic field, if the coil cannot be moved (without causing a change in magnetic force), electricity cannot be produced. ?
In other words, changes in magnetic force cause the coil to generate electricity. This principle is called electromagnetic induction and the current generated is called induced current. ?
When the magnet is close tothe coil, current will flow to the coil in the direction of the arrow. ?
On the other hand, if the magnet is further from the coil, the current will flow in the opposite direction of the arrow. Of course, if the magnet is not moved, the magnetic field will not change and no electricity will be generated. ?
This electromagnetic induction can also be used in a simple generator for bicycles. ?
If you install a generator on the tire of a bicycle, the magnet inside the generator will rotate with the help of the rotation of the tire. At this time, the strength of the magnetic field near the coil changes, which can cause an induced current to flow to the coil. ?
This is the principle of electricity production, which can turn on the bicycle lights. ?
What is closely related to the production of electricity is the generator of the electricity company. ?
Hydroelectric power generation uses hydraulic energy tour spin a propeller mounted on a generator, replacing the rotation of bicycle tires, causing the magnet to rotate and produce electricity. ?
Thermal or nuclear power generation first uses a boiler or atomic furnace to create high temperatures, then uses the heat to evaporate water to produce steam. These vapors are sprayed towards the turbine installed on the generator. to produce electricity. The machine runs to produce electricity.
A. From the formula P=ρgh, it can be seen that the relationship between liquid pressure and depth is proportional. By observing the image, we see that the pressure and depth of the water. on a certain point inside the image are not complete. is proportional to pressure, but pressure changes with depth first slowly and then quickly, so A is false;
B according to the formula Q=I2Rt. , we see thatthe relationship between the heat generated by the current passing through the conductor and the current is the current. The heat generated by a conductor is proportional to the square of the current. By observing the image, we see that the relationship. between the two physical quantities reflected in this image is incorrect, therefore B is false.
C. From the formula Q=qm, it can be seen that the heat released by the complete combustion of the fuel is proportional to the mass, and the picture also reflects that the relationship between the heat released by the complete combustion of the fuel is proportional to the mass. combustion of fuel and mass is directly proportional, so C is correct;
D From the formula V=
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