Light. Quantum particles impeding on an object. Electromagnetic waves striking an object.
An incident ray is a ray of light that strikes a surface or boundary separating different mediums. It is the initial ray of light before it interacts with the surface, reflecting, refracting, or being absorbed.
Refracting
The material is called a photoemissive material.
A material that reflects or absorbs any light that strikes it is opaque.Tranlucent or transparent materials allow some or all light to pass through.
A material that reflects and absorbs all light that strikes its surface is called a perfect absorber, or a blackbody. It absorbs all incident light and reflects none, resulting in a black appearance.
It is called a halo. It's a result of moonlight reflecting and refracting in tiny ice crystals located in clouds or the upper atmosphere back down to earth.
A reflecting telescope has both magnifying mirrors and lenses to focus the image on the eyepiece. A refracting telescope uses only lenses to magnify and focus. A reflecting telescope can be much smaller, because the light can travel through the barrel of the telescope several times, being magnified with each reflection. This is why most large modern telescopes are reflectors.
Those terms are most commonly used for optical telescopes. However, the same design can be used for non-visible frequencies; for example, radio telescopes of the "satellite dish" variety are essentially reflecting telescopes.
When light strikes a convex lens, the light beam converges to a point called the focal point. This is due to the lens refracting or bending the light rays towards a central point. The distance from the lens to the focal point is called the focal length.
A refracting or refractor telescope is a dioptric telescope that uses a lens as its objective to form an image. The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used in other devices such as binoculars and long or telephoto camera lenses.There are two basic types of telescopes, refractors and reflectors. The part of the telescope that gathers the light, called the objective, determines the type of telescope. A refractor telescope uses a glass lens as its objective. The glass lens is at the front of the telescope and light is bent (refracted) as it passes through the lens. A reflectortelescope uses a mirror as its objective. The mirror is close to the rear of the telescope and light is bounced off (reflected) as it strikes the mirror
A reflector telescope collects light with a mirror. The mirror is located at the back of the telescope and reflects the incoming light to a focal point where it is then collected by an eyepiece for viewing.
A refracting device is called a lens. It is an optical device that is designed to refract light in a way that converges or diverges the light rays to create an image.