Current is the rate of flow of charges.
Category: Combined Physics
Define electrostatic charging by friction.
Electrostatic charging by friction is a process in which surface electrons are transferred from one electrical insulator to another electrical insulator when the insulators are rubbed together.
Define electric field.
An electric field is a region in which charged particles experience an electric force.
Define echo.
An echo is a reflected sound wave bouncing off hard surfaces.
Define ultrasound.
Ultrasound is a sound which has the frequency above human hearing range, above 20 000 Hz.
List the components of electromagnetic waves, from the lowest frequency to highest frequency.
Radio waves, Microwaves, Infrared rays, Visible light rays (ROYGBIV), Ultraviolet rays, X-rays, Gamma rays.
(Ronald Mcdonald Is Very Ugly Xcept Gary!)
List the properties of electromagnetic waves.
- They transfer energy from a wave source
- They are transverse waves
- They travel with the same speed of 3×108 m/s in vacuum
- They can travel through vacuum. No medium required for its transmission.
- They travel in straight lines.
Define focal length.
Focal length is the distance between the optical centre and the focal point.
State the Laws of refraction.
First Law of Refraction:
The incident ray, the normal and the refracted ray all lie in the same plane.
Second Law of Refraction:
The ratio of sine of the angle of incidence to the sine of the angle of refraction is a constant.
(sin i / sin r = constant)
Define Refraction of light.
Refraction of light is the bending of light as it passes from one optical medium into another optical medium of different densities.