Final answer:
High-voltage transmission wires are not insulated; instead, they are held aloft by insulators. Using a pipe over the handle of a wrench increases torque but risks breaking the bolt. Dropping a bar magnet through a copper tube induces an electric current according to Lenz's Law.
Step-by-step explanation:
The statement about high-voltage wires being insulated is false. High-voltage transmission wires are not wrapped in an insulating material because they are suspended high above the ground, which itself acts as an insulator and they are separated from the metal towers by insulating connectors. The air around the wires also serves as an insulation. These measures prevent the current from unintentionally passing to the towers or to the ground.
When mechanics use a length of pipe over the handle of a wrench, this allows them to apply a greater torque to the bolt. The extended handle increases the moment arm, which in turn requires less force to achieve the same torque. However, this also increases the risk of over-torquing the bolt, potentially causing it to break or damaging the threading.
Lastly, dropping a bar magnet through a copper tube indeed induces an electric current in the tube. This is due to Lenz's Law, which states that the induced current will create a magnetic field that opposes the motion of the magnet, slowing its fall. This is a direct demonstration of electromagnetic induction.