How long does it take to turn a 920 W heater into steam 1 kg of water having a temperature of 100

How long does it take to turn a 920 W heater into steam 1 kg of water having a temperature of 100 degrees with an efficiency of 80%.

The heater efficiency can be expressed by the formula:
η = A / Q, where η is the efficiency (η = 80% = 0.8), A is the value of the perfect work of the heater, Q is the energy expended by the heater.
A = L * m, where L is the specific heat of vaporization of water (L = 2260 kJ / kg = 2260 * 10 ^ 3 J / kg), m is the mass of water (m = 1 kg).
Q = Р * t, where Р – heater power (Р = 920 W), t – heating time (s).
η = A / Q = L * m / (P * t)
Let us express and calculate the heating time:
t = L * m / (P * η) = (2260 * 10 ^ 3) * 1 / (920 * 0.8) = 3071 s.
Answer: The heating time is 3071 s.