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The sliding resistor is connected to the circuit by changing the resistance______ To change______ &The size of the
According to the principle of the sliding rheostat, the sliding rheostat changes the resistance by changing the length of the resistance wire connected to the circuit, because the power supply voltage remains unchanged, according to Ohm's law, it changes the current in the circuit
Connect a bulb marked with "220 V, 100 W" to the circuit of 110 V for 10 h to calculate the power consumption of the bulb
Hurry!
Resistance of lamp r = u ^ 2 / P = 220 * 220 / 100 = 484 Ω
Connected to 110V circuit, P = u ^ 2 / r = 110 * 110 / 484 = 25W
10h consumed electric energy w = Pt = 0.025kw * 10h = 0.25kw. H = 0.25 degree
0.5 degrees -- 500 kWh
According to the square of u divided by resistance = w, 25W = 0.025 kwh, 1kW / h = 1 kwh
10 hours = 25 * 10 = 250W = 0.25 kWh
The density of mercury is 13.6 × 103kg / m3, and that of aluminum is 2.7 × 103kg / m3
How many grams of mercury do you need to fill a hollow aluminum ball with water, which has a volume of 30 cm3 and a mass of 27 G
Hollow volume = 30-27 △ 2.7 = 20 cc
Mercury mass = 20 × 13.6 = 272g
Do not understand can ask, help please adopt, thank you!
The sliding rheostat changes the resistance by changing what is connected to the resistance wire in the circuit?
Adjust the resistance by changing the length
Resistance = P * L / s2
P is determined by the material characteristics of the resistance wire. If the material is determined, P is a fixed value;
L is the length of the resistance wire in the access circuit
S2 refers to the cross-sectional area of the resistance wire
If the electric lamp marked with "220 V, 100 W" is connected to the 110 V circuit, what is the current passing through the lamp? What is the actual power at this time?
2272a, the actual power is 25W
R = square of U / P = (220 * 220) / 100 = 484 ohm
Connected to 110V I = u / r = 110 / 484 = 0.2272a
P = square of U / r = (110 * 110) / 484 = 25W
Or P = u * I = 110 * 0.2272 = 24.992w, about 25W
The density of logs is 0.6 * 10 cubic kilogram / cubic meter, using 10 logs of 2m in length and 0.5 square meter in cross section
The density of logs is 0.6 * 10 cubic kg / m3. When the raft is composed of 10 logs with a length of 2M and a cross-sectional area of 0.5 square meters, how many kg of cargo can it carry at most?
I only wrote one step, then I couldn't think of it
First of all, it means that the floating should not submerge the cargo, otherwise it can not be calculated, because the cargo itself is an unknown quantity; when the sum of the weight of the cargo and the weight of the raft = the buoyancy of the raft when it is completely submerged, the cargo is the heaviest. P (log density) V (log volume) G + G = P (water density) V (log volume) GG = mg
The working principle of the electric blanket, preferably the internal circuit diagram. How much is the temperature when using? How to choose the resistance?
Switch three gears... Half temperature when diode is connected. High temperature when diode is directly connected. Off. Depending on the influence of ambient temperature and quilt thickness, the electric blanket is usually more than 30 degrees. It is mainly composed of heating element, base core, fabric, power line, junction box (the connection part between heating element and power line), control switch (or thermostat), etc
A lamp marked with "220 V, 100 W", when it is connected to 110 V circuit, what is the actual power of the lamp
Resistance of lamp: r = u & # 178; / P = 220 & # 178; / 100 = 484 Ω
When the resistance in the circuit is connected to 110V, it does not change,
Actual electric power: P real = u real & # 178 / r = 110 & # 178 / 484 = 25W
A: its actual power is 25W
Become a quarter.. 25W
The original u = 220 V, now u = 110 V = 1 / 2 u, the original P = (1 / 2 U) ^ 2 / r r remains unchanged
So p = 1 / 4 * 100 = 25W
R lamp = u ^ 2 / P = (220 V) ^ 2 / 100 W = 484 Ω P real = u real ^ 2 / R lamp = (110 V) ^ 2 / 484 Ω = 25 W
The upper sole is 2.5cm, the height is 9cm, and the area is 31.5cm
(trapezoid)
Trapezoid area = (upper bottom + lower bottom) * height / 2
So the bottom is 4.5cm
Slide rheostat by changing resistance wire______ To change______ So as to gradually change the voltage in the circuit______ .
The sliding rheostat changes the resistance by changing the length of the resistance wire in the circuit, so as to gradually change the current in the circuit
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