Physical meaning of dielectric constant What is the unit symbol of dielectric constant?

Permittivity is also called dielectric constant, permittivity or permittivity. It is a coefficient indicating the characteristics of insulation capacity, expressed by the letter ε, and the unit is fa / m
It is a proportional constant between the electric displacement and the electric field strength. In a free space (a vacuum), this constant is 8.85 × 10-12 times Faraday / meter (F / M). In other materials, the dielectric coefficient may vary greatly, often much larger than the value in vacuum, and its sign is EO
In engineering applications, the permittivity is often expressed in the form of relative permittivity rather than absolute value. If EO represents the permittivity of free space (8.85 × 10 to the - 12th power f / M), and E is the permittivity in the material, then the relative permittivity (also called permittivity) of the material is given by the following formula: ε 1 = ε / ε o = ε × 1.13 × 10 to the 11th power
The dielectric constant of many different substances is more than 1.. These substances are usually referred to as insulators or insulators. The commonly used insulators include glass, paper, mica, various kinds of ceramics, polyethylene and specific metal oxides. Insulators are used for alternating current. Foam plastics are made of polystyrene, polyvinyl chloride and polyurethane resin, and polystyrene 2.2.6. Permittivity can be divided into relative permittivity and effective permittivity. We usually call it relative permittivity. The relative permittivity of silicon is 11.9. (AC), capacitors and transmission lines of acoustic wave (AF) and radio wave (RF)
When a capacitor plate is filled with a dielectric constant of ε, the capacitance increases by ε times

How to square the dielectric constant of plasma in tensor form?
The dielectric constant of plasma is tensor, written in matrix form, and some elements in it are complex. Sometimes we encounter the situation of square root of dielectric constant, how to deal with it? Is it to square each element directly? Thank you!

It is to square each element directly. The newly generated tensor is the square root of the original tensor. You can also ask this question here. Many people don't understand tensor

Help me solve an application problem of one variable linear equation in junior high school,
A is faster than B at a speed of 7:5. When they are going in opposite directions, a and B start from AB and meet each other 0.5 hours later. When a and B are going in the same direction, how long does it take a to catch up with B?

Let a catch up with B in X hours
Suppose that the velocity of a is 7 and that of B is 5, then the distance between AB and ab is (7 + 5) × 0.5 = 6
7x+5x=6+5x
The solution is x = 6 / 7

Two practical problems in preparatory class
1) A plane can fly continuously for up to 7 hours in the air. If the speed is 600 kilometers per hour when it flies out and 450 kilometers per hour when it flies back, how many kilometers should it fly back?
2) The admission fee of a park is 10 yuan per person, and there is a 20% discount for group tickets for more than 20 people (including 20 people). When the number of people is less than 20, it is cheaper to buy group tickets for 20 people than individual tickets?

1. Let fly out time be X
600x=450(7-x)
x=3
So the plane should fly back as far as 3 kilometers
2. Set the number of people as X
Group tickets for 20 people need 20 * 10 * 0.8 = 160
sixteen thousand and sixteen
So it's cost-effective to have 17, 18, 19 people

There are two bottles of coke, bottle a and bottle B. the content of bottle a is 512 kg less than that of bottle B. now take 14 kg from bottle B and pour it into bottle A. how many kg more coke is in bottle B than that of bottle a?

512-14 × 2, = 512 − 12, = 5 (kg); a: the coke in bottle B is 5 kg more than that in bottle a

A practical problem in preparatory class
The weight of barrel a is 5.2kg, and that of barrel B is 8.6kg. How many kilograms can barrel a pour to barrel B to make the weight of barrel B three times that of barrel a?

It's very simple
1. Set a barrel to pour x kg to B barrel, so that the weight of B barrel is three times that of a barrel
3(5.2-x)=8.6+x
15.6-3x=8.6-x
-2x=-7
x=3.5
A: if you pour 3.5kg into barrel B, the weight of barrel B will be three times that of barrel a

1. A train is 160 meters long. It takes 30 seconds for the whole train to cross the 440 meter bridge. What is the speed of the train?
2. My mother bought 5 jin of oranges and 4 jin of bananas for 22 yuan. It is known that the price of 3 jin of oranges is equal to that of 2 jin of bananas. How much are each of 1 jin of oranges and 1 jin of bananas?
3. A two place decimal is rounded off to obtain an approximate number of 3. The minimum number is and the maximum number is_ .
4. The adjacent sides of a parallelogram are 6 meters and 5 meters long respectively_ It has the largest area when the area is square meter.
5. There are m bags of rice in warehouse A, and the number of rice bags in warehouse B is three times of that in warehouse a .
6. The length of the other right side of a right triangle with a length of 12 cm and an area of 72 square cm is centimeter
7. When the value of X is_ The value of. 5x + 0.1 is 0.4 when B is__ In this case, 2b = B + 2
8. The height of a trapezoid is 4.8. If the upper and lower bottoms remain unchanged, the area will increase by 86 square meters when the height increases to 22 meters. The original area of the trapezoid is_ .
9. The sum of number a and number B is 171.6. If the decimal point of number B moves one place to the left, the two numbers will be equal, and number a is The number B is__ .

1. Suppose: the speed of the train is v
30v=440+160
v=20
A: the speed of the train is 20 meters per second
2. Set: one Jin orange X Yuan, one Jin banana y yuan
5x+4y=22
3x=2y
x=2 y=3
Answer: a jin of orange 2 yuan, a jin of banana 3 yuan
3. Minimum 2.50 maximum 3.49
4. Vertical 30
5. The sum of rice in warehouse A and warehouse B
6、12
7、0.06 2
8、24
9、15.6 156

Elder brother elder sister helps, calculates the elementary school mathematics problem, calculates the problem o (∩)_ ∩)O~
Write down the process! (^__ ^)
①[2007-（8.5×8.5-1.5×1.5)÷10]÷160-0.3
②3²+1/3²-1² + 5²+1/5²-1² + 7²+1/7²-1² +...+ 1993²+1/1993²-1² + 1995²+1/1995-1²
shed tears of gratitude!

First
=[2007-（8.5²-1.5²)÷10]÷160-0.3
=[2007-（8.5+1.5)*(8.5-1.5)÷10]÷160-0.3
It's not hard at the back

1. The road construction team built a highway. On the first day, it built four seventh of the total length, and on the second day, it built the remaining three fifths. At this time, there are still 42 kilometers left to be built. How many kilometers is the total length of this highway?
2. A, B and C have a total of 2280 yuan. The ratio of money between a and B is 2:7, and the ratio of money between B and C is 3:7?

1.42 ± (1-3 / 5) ± (1-4 / 7) = 245km
2. The ratio of a, B and C is 6:21:49
2280 ÷ (6 + 21 + 49) = 30 yuan, 30 × 6 = 180 a, 30 × 21 = 630 B
30 × 49 = 1470

1. The length of an iron wire is 100cm. If the iron wire is enclosed into a square, how long is the longest side? If it is enclosed into a rectangle with a length of 30cm and a width of 16cm, how many centimeters is left?
2. The ticket of the amusement park is 45 yuan per person. If there are many people going, you can buy group tickets. There are 200 students in grade 2. If you buy group tickets, you can share 6000 yuan. How much cheaper is it for each person?
Use 10 1cm sticks to form a four side row. Its minimum area is (). Its maximum area is ()

1) The longest side length of the square is 100 △ 4 = 25cm
The remaining wire is 100 - (30 + 16) × 2 = 8cm
2) It's 45-6000 yuan / person, and 200 yuan / person is 15 yuan
3) The minimum area is (4cm & # 178;) and the maximum area is (6cm & # 178;)

Physical meaning of dielectric constant What is the unit symbol of dielectric constant?