Final answer:
The statement that dry-type transformers are filled with oil is false; they use air to cool. Isolation transformers are used for safety to separate a device from a power source, and step-down transformers reduce voltage from high to low levels. Inserting a dielectric in a capacitor increases capacitance, and wood doesn't easily conduct electricity but can do so in the case of lightning.
Step-by-step explanation:
True or False: Dry-type transformers are filled with oil to reduce overheating. The correct statement here is False. Dry-type transformers do not use oil for cooling; instead, they rely on air circulation to dissipate heat. They are designed to function without oil, which is used in other types of transformers to cool and insulate the transformer components.
Isolation transformer: An isolation transformer is a type of transformer that is used to transfer electrical power from a source of alternating current (AC) power to some equipment or device while isolating the powered device from the power source for safety reasons.
Step-down transformer: This type of transformer reduces voltage from a higher level to a lower level. It is true that it has more turns on the primary coil than on the secondary coil, and consequently, the secondary voltage is smaller than the primary voltage.
Dielectric and capacitor: Inserting a dielectric between the plates of a capacitor increases the capacitance but does not necessarily increase the energy of the capacitor. The correct statement regarding the impact of a dielectric is that it increases the capacitance which can potentially increase the energy stored if the voltage is kept constant.
True or False: Although wood is an insulator, lightning can travel through a tree to reach Earth. The correct answer is True. While wood is not a very good conductor, the extreme voltage of a lightning strike can overcome the resistive properties of wood, causing lightning to travel through a tree and reach the ground.
Regarding electric clothes dryers, it is possible to design the heating coils such that their magnetic fields cancel each other out, effectively reducing mutual inductance with the case of the dryer.