Find the equivalent resistance of the triangular bipyramid between the points
A) A and C
B) D and E
Assume the resistance of each brach to be R

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

$\frac{4 R}{5}, \frac{4 R}{3}$

$\frac{2 R}{5}, \frac{4 R}{3}$

$\frac{2 R}{5}, \frac{2 R}{3}$

$\frac{4 R}{5}, \frac{2 R}{3}$

answer is D.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

Resistor is connected in between A and C but not connected in between D and E.

(a) When a cell is connected in between A and C, the resistors betwen D, B and B, E will become ineffective [This is by symmetry or wheatstone’s beidge principle] becaus the points D, B and E will be at same potential. Now the equivalent circuit will be

It can be proved that $R_{AC} = \frac{2 R}{5}$

(b) When a cell is connected between D, E the points A, C will be at same potential. [This is also by symmetry or principle of balanced wheatstone’s

bridge circuit i.e. $\frac{R_{EA}}{R_{AD}} = \frac{R_{EC}}{R_{CD}}]$ and (B, C) will become ineffective.

Now the equivalent circuit is clearly $R_{DE} = \frac{2 R}{3} .$

Watch 3-min video & get full concept clarity