If in the circuit shown below, the internal resistance of the battery is `1.5 Omega` and `V_(P)` and `V_(Q)` are the potential at `P` and `Q` respectively, what is the potential difference between the point `P` and `Q`?

Options

A. Zero
B. `4 V(V_(P) gt V_(Q))`
C. `4 V (V_(Q) gt V_(P))`
D. `2.5 V V(V_(Q) gt V_(P))`

Answer

D

Explanation

Effective resistance of circuit `=(5xx5)/(5+5)+15=4Omega`
Total current in circuit,
`I=(20)/(4)=5A`
Current in arm APB or AQB`=(1)/(2)=2.5A`
`V_(A)-V_(P)=3xx2.5=7.5V`
`V_(A)-V_(Q)=2xx2.5=5V`
`V_(P)-V_(Q)=(V_(A)-V_(Q))-(V_(A)-V_(P))`
`=5.0-7.5=-2.5V`