The voltage supplying the current in the given circuit is _____.

V = IR
= 250 x 10^-6 x 100 x 10^3
= 250 x 100 x 10^(-6+3)
= 250 x 100 x 10^-3
= 25 x 1000 x 10^-3
= 25 x 10^3 x 10^-3
= 25 x 10^0
= 25 x 1 [Anything power 0 is 1]
= 25 volts.