
$=312 \Omega$
Now
$I _1=\frac{50}{372} \text { and } I _2=\frac{50}{600}$
$V _{ S }- V _{ T }=312 I _1-500 I _2$
$=41.94-41.67$
$=0.27 V$

$(A)$ $4$ if wires are in parallel
$(B)$ $2$ if wires are in series
$(C)$ $1$ if wires are in series
$(D)$ $0.5$ if wires are in parallel.

Reason : Kirchoff 's loop rule follows from conservation of momentum.


