Using an electric kettle, you can heat 3 liters of water from 20 degrees to 100 degrees in 15 minutes.

Using an electric kettle, you can heat 3 liters of water from 20 degrees to 100 degrees in 15 minutes. the boiler has an efficiency of 80%, and is connected to a network with a voltage of 220 V. What amperage it will consume in the network

To find the required current in the network, we apply the formula: η = Ap / Az = Sv * m * (tк – tн) / (U * I * t) = Sv * ρ * V * (tк – tн) / (U * I * t), whence we express: I = Sv * ρ * V * (tк – tн) / (U * t * η).

Constants and variables: Sv – heat capacity of water (Sv = 4200 J / (kg * K)); ρ – density (ρ = 100 kg / m3); V is the volume of heated water (V = 3 l = 3 * 10 ^ -3 m3); tк – final temperature (tк = 100 ºС); tн – initial temperature (tн = 20 ºС); U – mains voltage (U = 220 V); t is the duration of the boiler operation (t = 15 min = 900 s); η – boiler efficiency (η = 80% = 0.8).

Calculation: I = Sv * ρ * V * (tк – tн) / (U * t * η) = 4200 * 1000 * 3 * 10 ^ -3 * (100 – 20) / (220 * 900 * 0.8) = 6.36 A.