Resistance R1 = 60 ohm, R2 = 40 ohm. The total resistance of two resistors in series is () ohm. The total resistance of two resistors in parallel is () ohm

Resistance R1 = 60 ohm, R2 = 40 ohm. The total resistance of two resistors in series is () ohm. The total resistance of two resistors in parallel is () ohm

solution
In series, R total = R1 + R2 = 100
In parallel, 1 / R total = 1 / R1 + 1 / r2
=1 / R total = 1 / 60 + 1 / 40
=1 / R total = 4 / 240 + 6 / 240
=10/240
=1/24
So / R total = 24 Ω
Welcome to ask

Two constant value resistors R1 are marked with "10 Ω, 1 a", R2 is marked with "15 Ω, 0.6 a",
What is the maximum allowable voltage at both ends when they are connected in series? How many amperes are allowed for the main circuit current when they are connected in parallel?

According to u = IR, U1 = 10V, U2 = 9V are used in series, and the maximum allowable voltage at both ends is two small and medium 9V. At this time, the current is 0.6A. The voltage at R1 is 0.6 * 10 = 6V, so the total voltage at both ends is: 9 + 6 = 15V. When they are used in parallel, the same small voltage should be met. Because the voltages of the two resistors are the same, they are both 9vr1