1 For automobiles a taxpayer uses for business purposes, the portion of the business standard mileage rate treated as depreciation is 23 cents per mile for 2013, the same as in 2012. 2  The IRS also publishes a standard mileage rate for the use of a vehicle for medical or moving purposes.
What causes continuous rolling thunder when no lightning visible? Thunder is caused by the rapid expansion of super-heated air as electrical spark passes through. What causes the long (ie some several seconds) of rumbling when no lightning is visible even at night during tropical downpours?
A lot of theories has been discussed concerning causes and creation of thunder. In the third century BC, it was believed that thunder is caused due to collision of clouds. However, the most accepted theory was conceived in the 20th century. According to this theory, lightning causes thunder sound.