a) Potential difference between terminals of ‘a’ is 10 V.
i through a = 10 / 10 = 1A
Potential different between terminals of b is 10 – 10 = 0 V
i through b = 0/10 = 0 A

b) Potential difference across ‘a’ is 10 V
i through a = 10 / 10 = 1A
Potential different between terminals of b is 10 – 10 = 0 V
i through b = 0/10 = 0 A