The total electrical resistance between the points A and B of the circuit shown, is

Options

A. `9.23 Omega`
B. `15 Omega`
C. `30 Omega`
D. `100 Omega`

Answer

A

Explanation

In branch, (1) resistors are in series.
`R_(1)=10+10+10=30 Omega`
In branch (3), 20 and 20 are in series
`therefore " " R_(3)=20+20=40 Omega`
The equivalent circuit of (1), (2) and (3) branches are in parallel.
`therefore (1)/(R_(eq))=(1)/(30)+(1)/(30)+(1)/(20)+(1)/(40)=(4+6+3)/(120)=(13)/(120)`
`E_(eq)=(120)/(13)=9.23 Omega`