Five resistances are connected as shown in figure. The effective resistance between A and B is

Options

A. `10/3 Omega`
B. `20/3 Omega`
C. `15Omega`
D. `6Omega`

Answer

D

Explanation

This is balanced Wheatstone's bridge. Thus, the resistance `7 Omega` is ineffective and `5 Omega` and ` 4 Omega` are in series and `10Omega` and `8 Omega` are in series.
Thus, `R_(s1)=5+4=9 Omega` and `R_(s2)=10+8=18 Omega` are in parallel, so effective resistance is ,
`R_(p)=(R_(s1)xxR_(s2))/(R_(s1)+R_(s2))=(9xx18)/(9+18)=6 Omega`