There are two resistors, R1 = 10 Ω, R2 = 15 Ω. What is the total resistance after they are connected in parallel

There are two resistors, R1 = 10 Ω, R2 = 15 Ω. What is the total resistance after they are connected in parallel

The reciprocal of the total resistance in parallel is equal to the sum of the reciprocal of each resistance, r = r1r2 / (R1 + R2) = 10 * 15 / (10 + 15) = 6 Ω

The known resistance R1 = 12 ohm. When it is connected in parallel with the unknown resistance R2 in the circuit, the measured current through R1 is 0.5A. When it is connected in series with the unknown resistance R2 in the same circuit (the voltage remains unchanged), the measured voltage at both ends of R2 is 2V. Calculate the voltage at both ends of the circuit and the resistance of the unknown resistance R2

In parallel, the voltage at both ends of R1 is equal to the power supply voltage,
Therefore, the power supply voltage U = R1 * I1 = 12 * 0.5 = 6V
In series, I2 = u (R2) / r2 = (6-2) / 12 = 1 / 3a
Therefore, R2 = u (R2) / I2 = 2 / (1 / 3) = 6 Ω

R1r2 is connected in series in the circuit, R1 = 40 Ω, R2 is a rheostat, and the current of R1 should be between 0.0.5a
Find (1) at least how much u is at both ends of the circuit, (2) at least how much R2 resistance is
(1) At least how large is u at both ends of the circuit (2) at least how much is R2 resistance.

U is at least 20V, R2 is at least 160 Ω

R1, R2 in parallel in the circuit, the main current is 1.5A, through R2 current is 0.6A, R1 = 10 Ω, calculate the resistance value of R2

It is known that the total current is 1.5A, the current flowing through R2 is 0.6A, then the current flowing through R1 is 1.5-0.6 = 0.9A, and because R1 = 10 Ω, the voltage of R1 is 0.9 * 10 = 9V, because the parallel voltage is equal, the voltage of R2 is also equal to 9V, according to Ohm's Law: R2 = 9V / 0.6A = 15 Ω