- The State of the Union Address (sometimes abbreviated to SOTU) is an annual message delivered by the president of the United States to a joint session of the United States Congress near the beginning of most calendar years on the current condition of the nation. The State of the Union Address generally includes reports on the nation’s budget, economy, news, agenda, progress, achievements and the president’s priorities and legislative proposals.
- f-number (Wikipedia)
An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is calculated by dividing the system’s focal length by the diameter of the entrance pupil (“clear aperture”). The f-number is also known as the focal ratio, f-ratio, or f-stop, and it is key in determining the depth of field, diffraction, and exposure of a photograph. The f-number is dimensionless and is usually expressed using a lower-case hooked f with the format f/N, where N is the f-number.