There are a series of parameters on the dial of Wangli home appliance energy meter, as follows: 220V 10 (20) a 50hz600revs / kW · h 2007 21 After working for 15 minutes, the turntable of the electric energy meter turns 150 times. How many kwh of electric energy is consumed? What is the power of the micro blog channel

There are a series of parameters on the dial of Wangli home appliance energy meter, as follows: 220V 10 (20) a 50hz600revs / kW · h 2007 21 After working for 15 minutes, the turntable of the electric energy meter turns 150 times. How many kwh of electric energy is consumed? What is the power of the micro blog channel

W=n/N=150r÷600r/kW·h=0.25kW·h
P=W/t=0.25kW·h÷ 0.25h=1kW=1000W

Xiao Ming's family has an electric kettle with the following name plates: rated voltage: 220 V; rated power: 840 W; frequency: 50 Hz; capacity: 4 L; bottle weight: 2 kg
Xiao Ming now puts 3l20 ° C water into the pot, and asks: ① the quality of the water in the pot; ② how many minutes it takes to boil the water under the rated voltage (excluding the heat loss, in the environment of 1 standard atmospheric pressure); ③ in the peak period of power consumption, the actual voltage of the kettle is only 90% of the rated voltage, then what is the actual power of the kettle?
Please write down the process,

①m=ρv=1×3=3（kg）
②Q=cmΔt=4.2x1000×3×（100-20）=100800
P=W/t
T = 100800 / 840 = 1200 (seconds) = 20min
③P=U^2/R
P'=(90%U)^2/R
=0.81x840
=680.4(W)

Xiaoming bought an electric kettle. The name plate of the electric kettle is as follows: v = 220 V, P = 1800 W, power frequency 50 Hz, capacity 4 L
(1) (2) how much heat does it need to absorb to heat the water from 25 ℃ to 100 ℃ (C water = 4.2 × 103J / (kg ·℃), regardless of heat loss)] (3) if the actual voltage is 198v, how many minutes does it take to boil the water? (regardless of heat loss, the result is rounded)

1. P = UII = P / u = 1800 / 220 = 8.18a2, m water = P water V, v = 4L = 0.004m ^ 3 = 1000x0.004 = 4kg, Q suction = C water, m water (t1-t0) = 4200x4x (100-25) = 1260000j3, resistance of hot water kettle: r = u ^ 2 / P = 220x220 / 1800 = 26.89 Ω, actual power. PST = u ^ 2 / r = 198x198 / 26.89 = 1458ww = q

As shown in the picture is Xiaoming's electric kettle and its name plate. He uses the electric kettle to heat 1.5kg water from 20 ℃ to 100 ℃. (1) how much heat does the water absorb? [cwater = 4.2 × 103J / (kg ·℃)] (2) if the electric kettle works normally and all the heat generated is absorbed by water, how long does it need to be heated?

(1) The heat absorbed by water: Q absorption = cm (t-t0) = 4.2 × 103J / (kg ·℃) × 1.5kg × (100 ℃ - 20 ℃) = 5.04 × 105J; (2) the kettle works normally, the power of the kettle P = P = 1500W, according to q = w = Pt, t = WP = q absorption P = 5.04 × 105J, 500W = 336s