The hotplate, which contains two parallel-connected spirals of 36 ohms and 72 ohms, is connected to a network

| June 19, 2021 | education

The hotplate, which contains two parallel-connected spirals of 36 ohms and 72 ohms, is connected to a network with a voltage of 36 V. Determine the power delivered to the hotplates.

R1 = 36 ohms.

R2 = 72 ohms.

U = 36 V.

N -?

The power of the electric current N is determined by the formula: N = I * U, where I is the current in the circuit, U is the voltage.

We express the current strength I in the circuit by Ohm’s law for the section of the circuit: I = U / R, where R is the total resistance of the circuit.

When the conductors are connected in parallel, the total resistance is determined by the formula: 1 / R = 1 / R1 + 1 / R2 = (R1 + R2) / R1 * R2.

R = R1 * R2 / (R1 + R2).

N = U ^ 2 / R = (R1 + R2) * U2 / R1 * R2.

N = (36 ohms + 72 ohms) * (36 V) ^ 2/36 ohms * 72 ohms = 54 watts.

Answer: the tile has a power of N = 54 W.



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