What is the voltage difference between x and y for given circuit?

In the given figure, the effective resistance in both the parallel wires are equal (both = 5Ω). Hence, the current divided in both the wires will be equal i.e., 2 A will get divided in both the wires equally.
Now, by applying Ohm's law (V = iR ),

${\mathrm{V}}_{\mathrm{x}}=\left(1\mathrm{A}\right)\times \left(2\mathrm{\Omega }\right)=2$ volts

${\mathrm{V}}_y=\left(1\mathrm{A}\right)\times \left(3\mathrm{\Omega }\right)=3\text{ volts }$

$\Rightarrow {\mathrm{V}}_y-{\mathrm{V}}_x=3-2=1\mathrm{V}$