【 Weak current College 】 e-mail production started with 100 questions (a) 】

First, the basics of electricity
1. What is the electric power have several? what are the important characteristics of electricity?
Electricity is the first electrified from the "friction" phenomena manifested in kind of a property. There are both positive and negative electricity. "Repulsive attracts the opposite sex" is motorized for important features.
2, how to understand "electricity is kind of a property"?
The real power comes from its own general conditions, the real itself there equal amounts of positive and negative, and therefore does not display the characteristics of electricity; for some reason when the physical loss of or to obtain certain charge, external displays electric characteristics.
3, "friction electrification" is the object becomes the only way a charged state, please describe?
Wrong. In addition to friction, heat, chemical change, and so on for other reasons can make objects into live State.
4. What is a conductor and an insulator? examples.
Conductive objects called conductor; extremely conductive objects called insulator. Metal and aqueous solution with impurities are conductors; plastic, air, drying of the wood is an insulator.
5, plastic rods and wool from friction can suck, small paper Xiao and metal cannot, therefore, the metal is not "triboelectrification"? why?
No, metal objects can also be "frictional electrification" only because metal is a good conductor of electricity, charge quickly through human-to-ground discharge and, therefore, does not display the charged state.
6. various conductor conductive properties are the same?
Not the same. For example the conductivity of copper is better than aluminum, aluminum electrical conductivity and good than iron. But with impurities in aqueous solution of conductive poor performance, but they still belong to the conductor.
Why 7, conductor and insulator conductive? not easy conductive?
Conductors can be moved in the charge, the insulator canmove charge very little so conductive conductor and insulator not conductive.
8, insulators, in any event, not conductive? examples.
Wrong. If the air in voltage reaches a certain intensity, ionization conductor. Lightning is under high pressure electrostatic air suddenly becomes a conductor of natural phenomena.
9. What is the "breakdown" phenomenon?
The original is an insulator material in high-voltage electric field becomes a conductor, a phenomenon known as the "breakdown", lightning is the air is a high-voltage electrostatic breakdown.
10. Why is also conductive body?
The human body contains a lot of other substances are dissolved in an aqueous solution, it will also be conductive.
11. how current is it?
Conductor to the free movement of the charge in power, to move a rule, form the current.
12, represents the current size of the unit is used which scientist named after his main contribution?
Represents the current size of the unit is France scientist named after ampere. The main contribution is the ampere of identified current and magnetic field force relations between.
13. the direction of the current in the conductor is required?
Current direction is customary to positive charge moving direction is positive.
14, conductivity of metal conductors depending on what the direction of movement?
Metal conductor rely on free movement of "free electron" conductive "free electron" negatively charged, its direction of movement and a positive move in the opposite direction.
15, often hear of "AC" and "DC", in the end is what? examples.
Working current size direction does not change over time is called the DC. Working current size direction over time is called AC. Flashlight on the DC, AC incandescent lighting is the family.
16, voltage is all about?
As the water level will maintain water pressure difference, the difference will have to charge electric force, potential difference, also called voltage.
17, voltageunits from which a scientist's name? his major contribution?
Voltage of the unit is taken from the invented "volts battery" scientist v name "v", hereinafter referred to as the "v", the symbol "V." His main contribution was invent "volts battery" is motorized use and research to create a very important condition.
18. What is the "proprietor"?
On the human body, the greater the voltage 36V, life-threatening. It requires less voltage limitation of voltage 36V is called.
19, illustrate everyday life often encountered voltage values?
Civil AC 220V; a section of the battery label called 1.5V; section of powerboy NI-CD rechargeable battery nominal voltage of typically around 1.2V; lead-acid batteries each set voltage about 2v. And so on.
20. How can I use dry batteries get higher voltage?
Line up the batteries get 1.5V multiplying of voltage, such as two batteries in series to get 3V voltage, 3 section to get 4.5V ... Such DUI.
21. What is power? examples.
The other forms of energy into electrical energy of the device is called power, such as the battery will chemical energy into mechanical energy to electrical energy: generator will translate into electrical energy; solar cells solar energy into electrical energy will be, and so on.
22, DC and AC power, what's the difference? please explain.
Provides DC power that, in the form of a DC power supply AC forms of power known as AC power, civil AC is on AC power, the battery is a DC power supply.
23. What is the load? examples.
Power-on the contrary, the electric energy into other forms of energy of the device is called load. As a lamp will light energy into electrical energy in the motor will be converted to mechanical energy.
24, you typically use the incandescent electric light is who invented?
United States inventor Thomas Edison.
25, what characteristics of magnetic field?
Magnetic field always exist two polar opposite magnetic strongest region, called the magnetic pole.Pole sub Arctic (N) and the Antarctic (S), its characteristics are: the same polarity repel each other, different polarity attract.
26, magnetic field is generated?
Movement of charge generated magnetic field, and magnetic phenomena from the charge of the movement.
27, first revealed the electricity to produce the magnetic field of scientists who are you?
19 century in the 1920s, Denmark physicist Oersted's first public demonstration of the power of the conductor makes magnetic needle produces series of experiments, which reveals the power and the close link between magnetic.
28, "compass" phenomenon shows?
The earliest by the Chinese invented the "compass", explains the Earth there is a large magnetic fields.
29, the first realization of the "magnetic electricity" scientists who are you?
United Kingdom scientist Michael Faraday's 1831, the "magnetic electricity" scientific experiments and research discovered electromagnetic phenomena.
30, who discovered the electromagnetic wave?
United Kingdom scientist Maxwell mathematical summing up the predecessors to the electric and magnetic research results, project changes the electromagnetic field that will spread in the form of electromagnetic waves around the space.
31, the first confirmed the existence of the scientists of electromagnetic waves? his name is used to indicate what physical units?
Maxwell's theory of electromagnetic waves by 15 years later, Germany youth Hertz developed an ingenious device, first confirms wave theory. His name is used to indicate a unit of frequency.
32. What is the electromagnetic frequency?
Unit of time to complete the number of changes to electromagnetic cycle is called the electromagnetic frequency, its units as "Hertz", hereinafter referred to as "Hershey" symbol "Hz". Common units there are "KHz" (kHz) and "MHz" (MHz).
33, radio waves and optical essence is the same?
Yes, radio waves are electromagnetic waves and visible, just differentfrequencies, the radio frequency is low. Radio waves and optical transmission speed.
34, wavelength and frequency is what?
Electromagnetic waves to complete a cycle of transformation, the electromagnetic transmission distance is known as the wavelength. Wavelength is the speed of light is divided by the frequency. The higher the frequency the shorter the wavelength.
35, often heard in wave and short-wave radio is what difference?
According to the frequency and wavelength of correspondence, the receive frequency in 500KHz to 1600KHz for medium-wave frequencies in the radio, receive to 30MHz 3MHz as between short-wave radio.
36, pioneered use of radio communication experiment, of which two scientists?
Italy's Marconi and the Russians Popov. Marconi was also awarded the Nobel Prize.
37. What is amateur radio communication activities?
Amateur radio communication activities as amateur business classified as international telecommunications Treaty, refers to "not for financial gain, which is designed for individuals to have interest in radio technology, and with the proper license to engage in self-training, communication and technology business". Free access to the International Telecommunication Union organized to amateur radio use of radio frequency resources, electronic technology, communication technology and information processing technology, learning, research and practice, significantly enhancing the participants in the technical, linguistic, cultural and geographic knowledge.
38. What is circuit? three elements "circuit"?
Current path is called circuit. Circuit must be closed, that is, positive electric charge from its power source, must be able to return to power of anode able to form the current, so the circuit also known as electric circuit. Power supplies, load, and connections between them, form the loop of wire is any essential element of a circuit.
39, circuit there are several status? what state is the most dangerous?
Circuit has three States: first, the looped circuit connected everywhere. 2. disconnect the circuit somewhere into shape without circuit, called open circuit or open circuit. Third, the existence of a certain part of the original circuit voltage in both accidents on, called short-circuit. With short circuit may damage the power supply unit and components, is a dangerous State, must be avoided.
40, what is a unit of electrical resistance? resistance is what scientist named after he's main contribution?
Circuit on the current role through obstacles and cause energy loss of some called resistance. Resistance of units with Germany physicist named after ohm. His main contribution is a very large number of trials, the study out of voltage, current, and resistance of the three electrical quantities, summing up the most basic circuit's law — the Ohm's law.
41. What is the "Ohm's law"?
The current in the conductor and conductor is proportional to the ends of the voltage, and inversely proportional to the resistance of the conductor. Or resistance when current with voltage of grows, the voltage constant current with resistance increases and decreases.
42, examples of what is in-line, what is the load is connected in parallel? assumes two light bulbs.
Two light bulbs in the circuit there are two possible connection. If two bulb one by one, by order of the connections before and after are called inline. The two ends of the lamp connected side by side is called parallel.
43, two resistors in series, the greater the resistance or shunt minimum??
In-line, parallel is smaller.
44, how to understand "electric power"? how to represent its size?
Different forms of energy transformation processes in the "credit" can be used to represent the relationship. Current of energy transfer to the load into other number that you can use electric power to represent the relationship. Electric power equal to the product of power and voltage units commonly used kWh. KWhcan also be used to measure the power consumption, at this point, l kWh is equivalent to the consumption of electricity "l".
45, 1000-watt bulb lit 2 hours, the electricity consumption of reactive power? how many units of electricity?
Electric power consumption, 2 2 kilowatt hour electricity.
46. What is power?
Unit of time doing electrical work size, is power. Can be used to measure the same electrical conversion capacity of electric power.
47, electric power and the load voltage, current%? units?
Electric power equal to the product of voltage and current, that is proportional to the relationship. The units are commonly used "Watts W".
48, multimeter measuring DC voltage corresponds to pay attention to?
Measuring DC voltage select greater than before the voltage value be measured voltage DC voltage rail, it is not necessary to disconnect the circuit, the red table amount received high potential client, the black table amount received low potential client.
49, multimeter measuring DC current should be aware of?
Measuring current, first disconnect the circuit to be measured, select is greater than the test circuit current of DC current, so that the current flows from the red table pen ammeter, from black table pen ammeter flow out.
50. how to use digital multimeter measurement resistance?
Try to select a pointer to the middle of the ohm, the test should be zero, and never use your finger to touch to be logging resistance or both ends of the table amount.