Question

you have one 100 ohm resistor what size resistor must you hook up in parallel in order to have a resistance of 99.0

Answer 1

Answer:

The resistor to be hooked up must be 9900 $\Omega$

Explanation:

Recall how resistors in parallel combine to render an equivalent resistor:

$\frac{1}{R_e} =\frac{1}{R_1} +\frac{1}{R_2}$

So we need to find which resistor (R2) we need to combine in parallel with resistor R1 (100 $\Omega$) in order to obtain an equivalent resistor Re (99 $\Omega$) :

$\frac{1}{99} =\frac{1}{100} +\frac{1}{R_2}\\\frac{9900\,R_2}{99} =\frac{9900\,R_2}{100} +\frac{9900\,R_2}{R_2}\\100\,R_2= 99\,R_2+9900\\R_2=9900\,\,\Omega$