Shadows change length due to the constant change in the angle of the sun’s rays. Light falling on an opaque object casts a shadow in the opposite direction to the source of light.Continue Reading
When the angle of the sun’s rays or any other source of light is shallow, the shadow tends to be longer. As the sun climbs higher, the angle of the sun’s rays becomes steeper and, consequently, shadows become smaller. When the sun is exactly overhead, sunlight falls vertically downwards, and the shadow is shortest. Similarly, even if an artificial source of light is exactly overhead, the shadow is beneath the object and shortest.
At sunrise and sunset, shadows are long but very faint, as light is not intense.Learn more about Optics & Waves
One of the most common uses of infrared rays is for wireless communication, such as with garage door openers, car-locking systems and handheld remote controls for televisions and other appliances. Since all objects emit some degree of infrared radiation, night-vision devices make use of their sensitivity to infrared rays to capture and transmit images when there is no visible light source. Heat-seeking missiles also rely upon infrared technology to track their targets in passive missile-guidance systems.Full Answer >
Gamma rays are used in many different ways; one of the most common uses is inspecting castings and welds for defects that are not visible to the naked eye. Another common use of gamma rays is in the treatment of certain types of cancer.Full Answer >
Ultraviolet radiation, X-rays and gamma rays all have wavelengths that are shorter than visible light. The ultraviolet spectrum ranges from 400 to 10 billionths of a meter, X-rays from about 10 billionths to 10 trillionths of a meter, and gamma rays less than 10 trillionths of a meter.Full Answer >
Convex mirrors work by reflecting parallel rays of light as if they all emanated from a single point somewhere behind the mirror. The distance between the actual surface of the mirror and this point depends on the level of curvature, with greater curvature resulting in lesser distance. Images in convex mirrors are distorted, with progressive compression of the image away from its center.Full Answer >