Final answer:
The statement about AC systems needing to be grounded within the cell line working zone is false, as grounding is essential for safety. High-voltage wires are bare and held by insulators, and electric-field lines from a positive charge spread radially outward.
Step-by-step explanation:
The statement that AC systems supplying fixed and portable electric equipment within the cell line working zone need not be grounded is false. Grounding is a critical safety measure to prevent electric shock in case of a fault. Devices like the isolation transformer can isolate the secondary circuit from the primary, hence preventing a direct path for current to earth, but grounding is still essential for safety.
High-voltage wires are indeed held aloft by insulating connectors but are not typically wrapped in insulating material; they are bare, making the statement false. Likewise, the statement regarding an isolation transformer is that it provides a safety feature by isolating the secondary circuit from primary, preventing a complete path for current to flow to earth, thus reducing shock hazards.
Electric-field lines do indeed radiate out from a positive point charge, making the statement about the electric-field lines spreading out radially and pointing outward true.