13. Find equivalent resistance across A and B
Answers
Answer:
IF ALL ARE ARRANGED INTO PARALLEL RESISTORS
THEN,THE EQUIVALENT RESISTANCE WILL BE
Solution :
Please refer the attachment first !!!
Step I : connect a battery across the circuit
Step II : write potential across resistors
[ The potential across both the ends of the wire will be the same .
Consider the unknown point as x
Step III : Rearrange the circuit
Point X and B
Three resistors are connected in parallel to each other .
Equivalent resistances for n no of resistors is connected in parallel is given by ,
➜ 1 / Rp = 1 / R 1 + 1 / R 2 .... + 1 / Rn
Hence ,
➜ 1 / Rp = 1 / R + 1 / R + 1 / R
➜ 1 / Rp = 3 / R
➜ Rp = R / 3 Ω
Point A and B
R and R/3 are connected in series with each other .
Equivalent resistances for n no of resistors is connected in series is given by ,
➜ Rs = R 1 + R 2 .... + Rn
Hence ,
➜ Rs = R + R / 3
➜ Rs = 4R / 3Ω
Now ,
R , 3R/2 , R are connected in parallel with each other .
➜ 1 / Rp = 1 / R + 3 / 4R + 1 / R
➜ 1 / Rp = 2 / R + 3 / 4R
➜ 1 / Rp = 8+ 3 / 4R
➜ 1 / Rp = 11 / 4R
➜ Rp = 4R / 11 Ω
The net equivalent resistance of the circuit is 4R/11 Ω