Zero 0.6/1kv power cable products for building

Zero 0.6/1kv power cable products for building

0.6/1kv means the rated voltage of the cable is between 0.6kv and 1KV
How to judge whether a natural number can be divided by 7
Help me to solve it as soon as possible! Kneel down and ask for help from math experts!
Tail cutting method:
If the number of one digit of an integer is truncated, and then two times of the number of one digit is subtracted from the remaining number, if the difference is a multiple of 7, then the original number can be divided by 7. If the difference is too large or it is difficult to see whether it is a multiple of 7 by mental arithmetic, we need to continue the above process of "truncation, multiplication, subtraction and difference checking" until we can make a clear judgment. For example, the process of judging whether 133 is a multiple of 7 is as follows: 13-3 × 2 = 7, So 133 is a multiple of 7; for example, the process of judging whether 6139 is a multiple of 7 is as follows: 613-9 × 2 = 595, 59-5 × 2 = 49, so 6139 is a multiple of 7, and so on
Tail cutting method:
Let P = a1 + A2 * 10 + a3 * 10 ^ 2 +... + a (n-1) * 10 ^ (n-1) + an * 10 ^ n
q=a2+a3*10+...+a(n-1)*10^(n-2)+an*10^(n-1)-2a1
2p+q=21(a2+a3*10+...+an*10^(n-1))
And because 21 = 7 * 3, if P is a multiple of 7, then q is a multiple of 7
The last three methods are as follows
The difference between the last three digits of the number and the number before the last three digits (or vice versa) can be divided by 7, 11 and 13. The number can be divided by 7, 11 and 13
For example: 1005928
Last three digits: 928, before last three digits: 1005 1005-928 = 77
Because 7 | 77, so 7 | 1005928
The last three methods are briefly proved as follows
Let a number be ABCDEF = ABC × 1000 + def = ABC × 1001-abc + def = ABC × 7 × 13 × 11 - (abc-def), so long as abc-def can be divisible by 7, then ABCDEF can be divisible by 7
If the number of digits of an integer is truncated, and then 2 times of the number of digits is subtracted from the remaining number, if the difference is a multiple of 7, then the original number can be divided by 7.
What is this household appliance that consumes 0.3 kwh of electricity in 20 minutes
A. Electric fan
B. Fluorescent lamp
C. Order rice pot
D. Television
20 minutes = 1 / 3 hour, that is, the power of electric appliance is 0.9Kw,
Power cable za-yjv-5 * 16, what do the letters and numbers mean?
Za is class a flame retardant, YJV is XLPE insulated PVC sheathed power cable, 5 refers to 5 copper cores, each with a cross section of 16 square mm
N is a natural number within 100, so how many n can make 2 ^ n-1 divisible by 7? Please write down the problem-solving process, the answer is 34
When n = 3K [K is a natural number], 2 ^ n-1 must be divisible by 7. When n = 3k, 2 ^ n-1 = 2 ^ 3K-1 = 8 ^ k-1 = (7 + 1) ^ k-1. According to the quadratic expansion, we get = 1 * 7 ^ k + P1 * 7 ^ (k-1) + P2 * 7 ^ (K-2) + +PK * 7 + 1] - 1 each term contains a factor 7, which can be divided by 7
It doesn't seem to work
Xiaohua found that the number of meters changed by 1.2kW in 40min A kind of h. What is the actual power consumption of his household appliances______ W. If the electric energy meter is marked with "220 V & nbsp; & nbsp; 2.5 (10) a", can an electric rice cooker with a rated power of 800 W be connected to the circuit______ .
(1) Because the energy consumed in 40 minutes is 1.2 kW · h; the actual power consumed by electrical appliances is: P = wt = 1.2 kW · H23 H = 1.8 kW = 1800 W. (2) the maximum allowable power of electric energy meter is: P = UI = 220 V × 10A = 2200 W. the total power in the circuit is: 1800 W + 800 w = 2600 w ＞ 2200 W
What does yjv-1kv-4 * 2 5 + 1 * 16 zryjv-1kv-5 * 10 nh-yjv-1kv - 4 * 6 power cable symbol mean
YJ -- cross linked polyethylene insulation
V --- PVC sheath
Zr -- Flame Retardant
NH -- refractory
1kV --- voltage level
4 * 25 + 1 * 16 -------- cross sectional area of 4-core conductor 25 square mm + 1-core 16 square mm (ground wire)
For example, yjv-1kv-4 * 25 + 1 * 16 represents a copper core cross-linked PVC insulated power cable with a rated voltage of 1kV and five copper conductors twisted together, of which the nominal cross-sectional area of one in the middle is 16mm2, and the nominal cross-sectional area of each of the other four is 25mm2.
For the type and specification of cable in the latter 2, Zr means flame retardant type, and NH means fire-resistant type. Other expressions are the same as above. ... unfold
For example, yjv-1kv-4 * 25 + 1 * 16 represents a copper core cross-linked PVC insulated power cable with a rated voltage of 1kV and five copper conductors twisted together, of which the nominal cross-sectional area of one in the middle is 16mm2, and the nominal cross-sectional area of each of the other four is 25mm2.
For the type and specification of cable in the latter 2, Zr means flame retardant type, and NH means fire-resistant type. Other expressions are the same as above. Put it away
Whether there is a positive integer m such that f (n) = (2n + 7) * 3 ^ n + 9 can be divisible by m for any natural number n. if there is, the maximum value of M can be obtained
It's the nth power of 3, not 3 * n
Besides, it's meaningless for you to use 0 as a reference. 0 is a natural number, which is changed into an hourly natural number in a certain year. There are not many people who think so now, except in the choice of filling in the blanks. If you really think 0 should be included, then the greatest common divisor of 16 and 36 is 4
In fact, the questioner's question is less than one, and the condition n belongs to n*
There is an electric energy meter marked with 3000 rpm, and an electric appliance makes the electric energy meter rotate 320 RPM in 10 minutes, so as to calculate the electric energy and power consumed by the electric appliance
The electric energy consumed by the appliance
320 / 3000 = 8 / 75 kWh
power
16 / 640 w = 60 / 8
107 kwh in 10 minutes,
Power P = 320 * 3600 * 1000 / 3000 / 600W = 640w
W = 3.6 times 1000000j divided by 3000 and then multiplied by 320 equals 384000
P=w/t=384000/600=640
What is the meaning of yjv-0.6/1kv XLPE power cable?
It belongs to low voltage cable with voltage below 660V and 1000kV. YJV belongs to PVC material, which is the outer insulation material of cable copper wire