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When the microwave oven works normally, the magnetron emits electromagnetic wave with a frequency of 2450MHz. How many meters is the wavelength of the electromagnetic wave
Wave speed = wavelength * frequency
Wavelength = wave velocity (c) / frequency (f) = 3 × 10 ^ 8m / s × 2450 × 10 ^ 6Hz = 1.23 × 10 ^ (- 1) M
The resistance of the heating wire of an electric water heater is 22 Ω, and the current is a when it is connected to a 220 V circuit. It uses 100 kilowatts of electricity when it works normally for 10 hours
Electric power of electric water heater
Current I = u / r = 220 / 22 = 10A
Power consumption w = uit = = 220x10x10 = 22000wh = 22kwt = 22kwh
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