Two coils connected in series have a resistance of 18 and when connected in parallel have a resistance of 4. Find the value of individual resistances of the coils.

Asked by Topperlearning User | 4th Jun, 2014, 01:23: PM

Expert Answer:

Let R1 and R2 be the resistances of the coils.

           
Multiplying (i) and (ii) we have =18x 4 =72
Now = = 182 – 4 (72) = 36
            =                …….(iii)
Solving eqs. (i) and (iii), we get R1=12 or 6; R2=6 or 12.

Answered by  | 4th Jun, 2014, 03:23: PM