The correct option is (c).
Explanation
Lightning is a high-voltage electric discharge resulting from the accumulation of electric charges in clouds. Safety precautions during a thunderstorm are primarily aimed at preventing the conduction of this massive electric charge through materials that connect the interior of a building to the outside environment, such as wires and pipes.
Statement-wise Analysis:
- Statement 1 is Correct: Lightning can strike telephone cords, electrical wires, and metal pipes. If lightning hits the external telephone lines, the electric discharge can travel through the wires to a person using a wired landline. Mobile phones and cordless phones are not physically connected to external wires, making them safer to use during a thunderstorm.
- Statement 2 is Incorrect: Plumbing systems often contain metal pipes, and tap water contains dissolved salts that make it a conductor of electricity. Lightning striking the building or nearby ground can conduct electricity through the pipes and water. Therefore, bathing or washing dishes under running water should be avoided to prevent electrocution.
- Statement 3 is Correct: While it is advisable to unplug sensitive electronic appliances (like computers and televisions) to protect them from voltage surges, electrical lights themselves do not pose a direct threat to human safety if left on. Standard safety guidelines state that electrical lights can remain on as they do not cause harm to individuals inside the house.
Key Takeaway:
During a thunderstorm, one should avoid contact with conductors connected to the exterior, such as wired phones and plumbing. Wireless devices are safe, and keeping lights on does not pose a personal safety risk.