JEE Main20199 Apr 2019Morning ShiftPhysicsCurrent ElectricityActual
A wire of resistance R is bent to form a square A B C D as shown in the figure. The effective resistance between E and C is: ( E is mid-point of arm C D )
Options
- AR
- B7 64 R
- C1 16 R
- D3 4 R
Correct answer
B. 7 64 R
Step-by-step solution
If the resistance of the wire is R , then each arm of the square has a resistance of R 4 . Accordingly. The resistance of segments DE and EC are R DE = R EC = R 8 . We can draw the resultant circuit as follows: Hence, 1 R e q = 8 R + 8 7 R 1 R e q = 56 + 8 7 R R e q = 7 R 64