Some examples of luminous objects are a burning candle, a light bulb, the sun and other stars, fluorescent materials and tube lights, among other things. Any object is considered luminous if it emits its own light, either through stored energy or energy supplied to the object, which contrasts with non-luminous objects such as the moon, wood, plastics and metals; these objects merely reflect light instead of providing their own.Know More
Luminous objects are responsible for our vision, as the human eye only perceives light that is being reflected into it. In darkness, where no luminous objects are present, the eye cannot perceive its surroundings.
In order for luminous objects to emit light, there must be a power source. The sun and other stars produce light due to the fusion of hydrogen atoms, the light bulb emits light due to the electrical energy flowing through it and the lit candle uses energy released by burning the wick. Fluorescent materials store energy given by other luminous objects and release light in wavelengths that cannot be seen in visible light. Some living organisms, such as fireflies, have natural luminescence, which allows them to convert the chemical energy stored in their cells into light. All luminous objects also release heat with the light they generate.Learn more about Physics
Contact forces are those forces that cause a change in another object because the objects are physically touching one another, according to Reference.com. Examples of contact forces include applied force, tension force, air resistance force and normal force.Full Answer >
Entropy is seen in situations that involve the dispersal of energy from a concentrated state to a less concentrated one, such as a hot pan cooling down, a tire blowing and releasing its air, the rusting of metal or cream mixing with coffee in a mug. These examples follow the definition of entropy, which is a measure of how energy and matter are dispersed within a system.Full Answer >
A bullet fired from a gun is an example of mechanical kinetic energy, while the gunpowder before firing is an example of chemical potential energy. Kinetic energy is the energy of a particle or wave in motion, while potential energy is the potential of this particle or wave to move.Full Answer >
An example of punctuated equilibrium is human evolution, in which species seem to remain stable for very long spans of time and then abruptly develop into new species, or in the rapid evolution of species isolated on islands. Punctuated equilibrium is a modified version of Darwin's law.Full Answer >