Question

The equivalent resistance between points A and B of fig is

A. $\dfrac{2}{3}\Omega$
B. $2\Omega$
C. $\dfrac{3}{2}$
D. $6\Omega$

Answer 1

From the circuit we can observe that it can be observed that there is some direct connection between some point from where current will pass due to 0 resistance and which is given by A-D and C-B so the resistance in between these points can be ignored.

Complete Step by step solution:
From A to D there are three paths A–C-D and A-D but, in path A-D the resistance in the circuit is zero but in path A-C-D two 2 ohm resistance are there so we can easily bypass them and select our required path A-D.

Now, from D to B one 2 ohm resistance is there so in total path A-D-B due to only 2 ohm resistance equivalent resistance is 2 ohm as shown in the above figure, but there are more possible ways to solve so we need to solve them accordingly and identify the equivalent resistance.

In path A-C-B only 2 ohm resistance is there and one bypass circuit to ignore rest of the resistance so in path A-C-B equivalent resistance is 2 ohm, now for path A-D-C-B similarly as above two path due to only one 2 ohm resistance in the path equivalent resistance is2 ohm .

So, the required answer is option B) 2 ohm.

Note:
In solving the circuit problems the most important thing to notice is, there any direct connection at some points in the circuit where the equivalent resistance will be zero, after that we need to consider about the rearrangements to convert the required circuit into series or parallel and solve accordingly to minimize the circuit.