Question

Two resistors connected in series have an equivalent resistance of 668.7 ?. When they are connected in parallel, their equivalent resistance is 141.4 ?. Find the resistance of each resistor.
(A) ______________ (Small Resistance)

(B) ______________ (Large Resistance)

Answer 1

R1 + R2 = 668.7 ohm ..........eqn1

R1 = 668.7 - R2 ........eqn2

1/(1/R1 + 1/R2) = R1*R2/(R1+R2) = 141.4 ohm .........eqn 3

putting value of R1+R2 in eqn 3 we get

R1*R2 = 141.4*668.7

(668.7 - R2 )*R2 =94554.18

R2^2 - 668.7R2 + 94554.18 = 0
solving this we get

R2 = 465.6349 or 203.065

taking 1st value of R2 we get

R1 = 668.7 - R2 = 668.7 - 465.6349 = 203.0651 .......

(A) _____ 203.065 _________ (Small Resistance)

(B) _____465.6349_________ (Large Resistance)