Two circular rings of identical radii and resistance of `36 ``Omega`` each are placed in such a way that they cross each other's center `C_(1) and C_(2)` as shown in `Fig. 7.54`. Conducting joints are made at intersection points `A and B` of the rings. An ideal cell of emf `20 V` is connected across `A and B`. Find the power delivered by the cell (in `10^(2) W`).

Options

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

Answer

B

Explanation

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.