Physics

Relative humidity is the ratio of the partial pressure of water vapour in an air-water mixture to the saturated vapour pressure of water at a prescribed temperature. The relative humidity of air depends not only on temperature but also on the pressure of the system of interest. If the system at State A is isobarically heated (heating with no change in system pressure) then the relative humidity of the system decreases because the saturated vapour pressure of water increases with increasing temperature.

Ultrasound refers to a sound wave with a frequency greater than the upper limit of human hearing, which is generally over 20 kHz. In general, humans can hear sounds with a frequency between 20 Hz and 20 kHz.

The Lyman series lies in the ultraviolet region of electromagnetic spectrum.

Blotting paper absorbs ink by the process of capillary action. The capillary action is based on the property of surface tension of liquid._x000D_ All unsized paper will absorb water. Blotting paper is not sized and made bulkier to provide capillary action for faster absorption of liquid._x000D_ Blotting paper has also been sold as a cosmetic to aid in the removal of skin oils and makeup.

A skid happens whenever the tires lose their grip on the road. Braking skids occur when the brakes are applied so hard that the front or rear wheels lose traction.