Which of the following resistor arrangement, A or B, has the lower combined resistance?

Question

Philoid · Accepted Answer

Equivalent resistance in arrangement A is 10 ohm as this is in series.

And in arrangement B both 10 ohm and 1000 ohm are in parallel.

So, combined resistance of arrangement B is caculated as follows:

1/R = 1/10 + 1/1000 = (100+1)/1000

R = 1000/101 = 9.9 ohm

So, arrangement in B has lower combined resistance.