Question

When two resistor of resistance R1 and R2 are connected in parallel the net resistance is 3ohm, when connected in series, its valueis 16ohm, calculate the values of R1 and R2?

Answer 1

When connected in parallel, 1/equivalent resistance =1/R1+1/R2=1/3 => R1+R2/R1R2=1/3=> R1R2/R1+R2=3.
When connected in series,equivalent resistance=R1+R2=16 ohm.
=>R1R2=48.
=> R1+48/R1=16.
=> R1^2+48 =16R1
=>R1^2-16R1+48=0
=> R1=12ohm and R2=4ohm.