Five straight wires P, Q, R, S and T were tested under identical conditions. Their measured potential difference and current are:
P: 12 V, 1.5 A
Q: 10 V, 0.50 A
R: 6 V, 0.60 A
S: 15 V, 1.0 A
T: 9 V, I (unknown)
If the resistance of T is numerically equal to the difference between the resistances of Q and P, determine the current I through wire T.