The circuit section consists of resistors connected in parallel with a resistance of 1.0 Ohm and a steel conductor 10 m

The circuit section consists of resistors connected in parallel with a resistance of 1.0 Ohm and a steel conductor 10 m long and 1.2 mm2 in cross section. Determine the amount of heat released in a given section of the circuit for 10 s, if the total current in the section is 3 A.

The data that we need to solve the problem: R = 1 Ohm;
lp = 10 m;
S = 1.2 mm²;
I = 3 A;
t = 10 s;
ρ = 0.13 Ohm * mm² / m2.
Find Q:
Let’s write a formula for solving the problem:
Q = P * t = I² * Rtot * t,
Rtot = R * Rp / (R + Rp),
Rп = ρ * l / S ⇒ Rtotal = R * ρ * l / (S * R + ρ * l).
Let’s substitute:
Q = 3² * [1 * 0.13 * 10 / (1.2 * 1 + 0.13 * 10)] * 10 = 347.24 J.
Answer: 347.24 J.