In a double subscript notation vab 7v denotes that In a doub

Solution

The notattion shows the Vab=+7v denotes the voltage between the two points in the circuits .Actually voltage is measured between the two points where as current flows through the circuit.Here V_ab means it is the voltage difference between the two points i.e. point a and point b . V_ab= V_a-V_b=+7v.