What is the value of the resistance `R_(1)` in the following circuit ?

Options

A. `30 Omega`
B. `45 Omega`
C. `60 Omega`
D. `80 Omega`

Answer

C

Explanation

By Kirchhoff's first law, current in the branch AD
= 2.25 A-1.5A=0.75 A
`because` The same P.D. is applied across `R_(2) and 30 Omega`
`therefore 0.75 R_(2)=1.5 xx30 therefore R_(2)=60 Omega`
and `because R_(1)=R_(2)=R therefore R_(1)=60 Omega`