Question

Two circular rings of identical radii and resistance of `36Omega` each are placed in such a way that they cross each others centre `C_1` and `C_2` as shown in figure. Conducting joints are made at intersection point A and B of the rings. An ideal cell of emf 20 volts is connected across AB. The power delivered by cell is:

A. 80 watt
B. 100 watt
C. 120 watt
D. 200 watt

Answer 1

Correct Answer - B
From the figure
`AC_(1)=AC_(2) =C_(1)C_(2)`=radius
`:. angle AC_(1)B=120^(@)`
Hence the resistance of four sections are shown in the figure
Hence equivalent resistance R across AB is
`1/R=1/24+1/12+1/12` or `R=4 Omega`
`:. ` Power =`(V^(2))/R=((20)^(2))/4=100 ` watt.