CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The resistance of all the wires between any two adjacent dots is R. The equivalent resistance between A and B as shown in the figure is

A
73R
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
76R
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
148R
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
None of these
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 76R
Since we need to evaluate the resistance between A and B, therefore connect a power source between A and B as shown below.

Since point D and E are connected to A by a wire of equal resistance, therefore both points D and E will be at equal potential. Hence we can neglect the resistance between D and E since no current will flow through it.
The circuit can be redrawn as shown.
For the branches CDG, EFH, GBI and BHJ, two equal resistances(R) are in series and their equivalent(2R) is in parallel with the third resistor(R).
Hence the equivalent resistance for each branch will be
Req1=2R×R2R+R=2R3
Hence the circuit reduces to the following circuit.
Now the circuit is symmeteric about AB. For one side of AB say left, three resistances R, 2R/3 and 2R/3 are in series. Their equivalent resistance will be,
Req2=R+2R3+2R3=7R3
Hence the circuit reduce to the one as shown below.
Since two equal resistance are connected across AB in parallel, there equivalent resistance will be,
RAB=12(7R3)=7R6
Hence option B is correct.

flag
Suggest Corrections
thumbs-up
19
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Series and Parallel Combination of Resistors
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon