Question

Find the resistance between (i) A and B and (ii) A and C of the network shown in the fig.​

Answer 1

Given: The resistance of each resistor: 10 ohm

To find: The resistance between (i) A and B and (ii) A and C

Solution:

• Now we have given the network with 8 resistors of 10 ohm each.

• For A and B:

• We can neglect the resistors near the point C and D.

• So we get the series of 3 resistors :

                      10 = 10 + 10 = 30 ohm

• Taking 30 ohm parallel with the resistor in the middle of line AB, we get:

                      1/R = 1/30 + 1/10

                      1/R = 4/30

                      R = 7.5 ohm

• So taking this 7.5 ohm in series with resistors near the point A and B, we get:

                      7.5 + 10 + 10 = 27.5 ohm.

• For A and C:

• We can neglect the resistors near the point B and D.

• So we get the series of 2-2 resistors in square:

                      1/R = 1/20 + 1/20

                      1/R = 2/20

                      R = 10 ohm

• Taking 10 ohm series with the resistor near the point A and C, we get:

                      R = 10 + 10 + 10

                      R = 30 ohm

Answer:

               So the resistance between A and B is 27.5 ohm and resistance between A and C is 30 ohm.