Two resistors are connected in parallel. It is known that R1 is equal to 30 ohm, I1 is equal to 2 A, R2 is equal to 4 ohm. Calculate the total voltage and total current

Two resistors are connected in parallel. It is known that R1 is equal to 30 ohm, I1 is equal to 2 A, R2 is equal to 4 ohm. Calculate the total voltage and total current

The total voltage is 30x2 = 60V, the total current is 2 + 60 / 4 = 17a

The linear equation of the chord of the parabola y2 = 8x with (1, - 1) as the midpoint is___ ．

Let y + 1 = K (x-1) be the equation of the straight line where the string is located, and ky2-8y-8-8k = 0 be substituted into the equation of parabola, and K = - 4 be obtained from Y1 + y2 = 8K = - 2, so the equation of the straight line where the string is located is 4X + Y-3 = 0, so the answer is 4x + Y-3 = 0

Relationship between resistance and temperature

The resistance of a conductor depends on the degree, material and cross-sectional area of the conductor and on temperature
The resistance of some materials increases with the increase of temperature, and the resistance of some materials decreases with the increase of temperature. This is the reason that the constant value resistance is generally made of alloy materials, which ensures that the resistance is not affected by temperature

4 (X-2) & # - 12 (X-2) + 9 = 0 solution

Formula:
4(x-2)²-12(x-2)+9=0
4[(x-2)²-3(x-2)]+9=0
4[(x-2)²-3(x-2)+(3/2)²-(3/2)²]+9=0
4[(x-2)-3/2]²=0
So (X-2) - 3 / 2 = 0
X = 7 / 2

Does 12V 20W light cost electricity

I can firmly answer that it costs electricity. Because if you use a 12V 20W lamp, you must also use a transformer. The reason why you spend electricity is the loss of the transformer. If you use a 220V 20W lamp, there will be less loss of a transformer. So your 12V 20W lamp costs electricity. For reference only!

M = a cube + B cube + C cube. N = a cube B + B cube C + C cube a
a. B. C is greater than 0

If ABC is greater than 0, then M > = n, which can be proved by sorting inequality or formula
3 (m-n) = rotation sum (2a + b) (a-b) ^ 2 > = 0

After connecting the two bulbs marked with "220 V & nbsp; & nbsp; 200 W" and "220 V & nbsp; & nbsp; 40 W" in series into the 380 V circuit, what will be burned is______ ．

The resistance of bulb 1 is: R1 = u2p = (220V) 2200W = 242 Ω, the resistance of bulb 2 is: R2 = u ′ 2p ′ = (220V) 240W = 1210 Ω, the two bulbs are in series, r = R1 + R2 = 242 Ω + 1210 Ω = 1452 Ω, the current in the circuit is: I = ur = 380v1452 Ω = 0.26A, the voltage at both ends of bulb 1 is: U1 = IR1 = 0.26A × 242 Ω≈ 63v, the voltage at both ends of bulb 2 is: U2 = u-u1 = 380v-63v ≈ 317v, the voltage at both ends of bulb 2 is far greater than its rated power It is the bulb that will burn out because of the pressure of 220 v. so the answer is "220 V & nbsp; 40 W"

Editor, relay publishing house, the first edition in May 2012. Cover design studio AA

Speed

A DC motor, with a coil resistance of 0.5 ohm, connected to a 12 volt power supply and passing a current of 2 A, is described
How much electrical energy is consumed in 5 minutes? How much electrical energy is converted into mechanical energy?

Electric energy IUT = 2 * 12 * 300 = 7200W
Heat energy: I ^ 2rt = 2 ^ 2 * 0.5 * 300 = 600W
Mechanical energy = 7200-600 = 6600w

How to calculate 78 * 32 + 78 * 67 + 78 with recursive equation

=78*(32+67+1)=78*100=7800