What is considered standard atmosphere?

Standard atmosphere is defined as a nominal atmospheric pressure and temperature that serve as a reference for various calculations in meteorology and aviation. The standard values are specifically set at 29.92 inches of mercury (in-Hg) and 15 degrees Celsius (°C) at sea level.

These values are essential because they provide a baseline from which other atmospheric conditions can be measured and compared. Understanding that standard atmospheric pressure is 29.92 in-Hg helps pilots and meteorologists assess the performance of aircraft and predict weather patterns under typical conditions. The temperature of 15°C is also significant, as it represents the average temperature of the atmosphere in standard conditions at sea level.

In this context, other options present pressures and temperatures that deviate from these standard values, making them unsuitable as references for standard atmosphere. Hence, the correct answer aligns with the established definitions used in the field.