Designed for a voltage of 220 V. How much heat does the heating element of an iron generate

Designed for a voltage of 220 V. How much heat does the heating element of an iron generate in 15 minutes if its resistance is 110 Ohm?

U = 220 V.

t = 15 min = 900 s.

R = 110 ohms.

Q -?

The amount of heat Q that is released in the conductor through which the electric current flows is determined by the Joule-Lenz law: Q = I * U * t, where I is the current in the conductor, U is the voltage at the ends of the conductor, t is the time of passage of the current.

We find the current strength according to Ohm’s law for a section of the circuit: I = U / R, where R is the resistance of the conductor.

The Joule-Lenz law will take the form: Q = U ^ 2 * t / R.

Q = (220 V) ^ 2 * 900 s / 110 Ohm = 396000 J.

Answer: when the current passes in the conductor, Q = 396000 J of thermal energy is released.