How to calculate the resistance of two 10 ohm resistors in parallel?

How to calculate the resistance of two 10 ohm resistors in parallel?

In parallel resistance, the reciprocal of the equivalent resistance is equal to the sum of the reciprocal of each resistance. According to this, no matter how many resistances are in parallel, and whether these parallel resistances are equal or not, we can immediately calculate the resistance value of the equivalent resistance by ourselves
You can decide whether to give more or not,

What are the resistance values of two 10 ohm resistors in parallel and series in the circuit?

When two 10 ohm resistors are connected in parallel, according to the calculation formula of parallel resistance 1 / r = 1 / R1 + 1 / R2, the total resistance after parallel connection is 1 / (1 / 10 + 1 / 10) = 5 ohm;
When two 10 ohm resistors are in series, according to the calculation formula of series resistance R = R1 + R2, the total resistance after series connection is 10 + 10 = 20 ohm

Why is it that if the total resistance of two resistors with equal resistance is 10 ohm after parallel connection, the total resistance of series connection is 40 ohm

Resistance parallel formula: 1 / R parallel = 1 / R1 + 1 / r2 if R1 = R2 = R, then r parallel = R / 2
So 10 = R / 2, r = 20 ohm
Resistance series formula: R series = R1 + R2 = 20 + 20 = 40 Ω

The total resistance is 36 ohm when the two resistors are in series and 8 ohm when they are in parallel___ And___ ．

According to the law of series and parallel connection, R1 + R2 = 36 Ω ①R1R2R1+R2=8Ω… ② The results show that R1 = 24 Ω, R2 = 12 Ω. So the answer is: 24 Ω; 12 Ω