# What is the resistance of an electric furnace if 28.8 kJ of heat is released within 1 minute at a current of 4 A?

July 31, 2021 | education

| According to the Joule-Lenz law, the amount of heat released by an electric furnace can be calculated using the formula:

Q = I ^ 2 * R * t, where Q is the released amount of heat (Q = 28.8 kJ = 28.8 * 10 ^ 3 J), I is the current strength (I = 4 A), R is the resistance of the electric furnace (Ohm), t – current passage time (t = 1 min = 60 s).

Let us express and calculate the resistance of an electric furnace:

R = Q / (I ^ 2 * t) = (28.8 * 10 ^ 3) (4 ^ 2 * 60) = 30 ohms.

Answer: The resistance of an electric oven is 30 ohms.