The electric iron is designed for a voltage of 220 V. How much heat is released in the heating

| June 19, 2021 | education

The electric iron is designed for a voltage of 220 V. How much heat is released in the heating element of the iron in 15 minutes, if its resistance is 110 ohms.

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 strength, U is the voltage, t is the time of passage of the current in the conductor.

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

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

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

Answer: Q = 396000 J of thermal energy is released in the iron.



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