Architecture Puzzler #542

What do you know about lightning? True or False:

The Empire State Building is struck about seven times a year.

On average, a commercial airliner is struck once during every 5,000 to 10,000 hours of flying time.

Roughly 2,000 thunderstorms are in progress over the earth's surface at any given time, producing as many as 100 cloud-to-ground discharges every second.

The Midwestern states experience the most lightning activity in the United States.

A lightning channel is about 8 inches (20 centimeters) in diameter.

A lightning flash could light a 100-watt bulb for three months.

If you combine two sound sources, each at 50 decibels (dB) what will be the resultant dB level? If you double the distance to a sound source, you reduce the dB by how much?