For example, an object that appears blue in white light will appear black in red light. Coloured objects in coloured lightĪn object appears to be black if it absorbs all the wavelengths of visible light. If white light is shone on an orange filter, only the orange wavelengths will be observed by the human eye. For example, an orange filter transmits orange light but absorbs all the other colours. When white light passes through a coloured filter, all colours are absorbed except for the colour of the filter. Lamp shades, shower curtains and window blinds are often translucent objects. Translucent materials transmit some light but are not completely clear. They are transparent because light is transmitted with very little absorption. Air, glass and water are common materials that are very good at transmitting light. When waves are transmitted, they continues through the material. Waves can also be transmitted at the boundary between two different materials. green light is reflected by the grass and detected by our eyes.red, orange, yellow, blue, indigo and violet are absorbed by the grass.The other wavelengths are reflected, and these are detected by our eyes.įor example, grass appears green in white light: These wavelengths are not detected by our eyes. When white light shines on an opaque object, some wavelengths or colours of light are absorbed. This will usually increase the internal energy of the particles.
When waves are absorbed by a surface, the energy of the wave is transferred to the particles in the surface. Waves can be absorbed at the boundary between two different materials. In order of increasing frequency (and decreasing wavelength ) these are given as:Įach colour within the visible light spectrum has its own narrow band of wavelength and frequency. The cartoon is an opaque medium because it does not permit the light to pass through and the objects can not be seen behind it.Within the visible light range of the electromagnetic spectrum, there is a spectrum of colour. The materials such as the wood, the stone, the metals, the plant leaves, the foil paper, the milk, the book, the cartoon, the human skin, and the black honey (molasses) are opaque to visible light. Most materials are opaque, When the light strikes an opaque object none of it passes through, most of the light is either reflected by the object or absorbed and converted to heat. The opaque medium is the medium that does not permit the light to pass through, and the objects can not be seen through the opaque medium. The objects on the other side of a translucent object appear fuzzy and unclear, As the translucent objects are semi-transparent, some ultraviolet rays can go through them, this is why a person behind a translucent object can get a sunburn on a sunny day. The object is made of molecules, and each molecule has electrons, capable of jumping to higher energy levels by absorbing energy. When light strikes an object, it can be transmitted, reflected or absorbed. The materials like frosted glass and some plastics, flint glass and tissue paper are called translucent objects, when the light transmits the materials, only some of the light passes through them. Transmitting Light Although light can travel through a vacuum, it can not travel through all objects. The translucent medium is the medium which permits only a part of the light to pass through and absorbs the remaining part, the objects can be seen through translucent medium less clearly than the transparent one. The transparent medium transmits all visible light, the color of a transparent object depends on the color of light that transmits, So if red light passes through a transparent object, the emerging light is red.Īlthough the water is a transparent medium, we can not see fish at the bottom of the sea as the thickness of the water at that point ( the bottom ) is large enough to prevent the light to pass through, B y increasing the thickness of the transparent medium, the quantity of light that passes through it decreases. The transparent medium is the medium which permits most light to pass through, the objects can be seen clearly through a transparent medium, the materials like the air, the pure water, the glass cup and the clear glass in a window are called transparent. The light transmits through different media with variable degrees, So, Media can be classified according to their ability to allow the light to pass through, into transparent medium, translucent (semi-transparent) medium, and opaque medium.
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