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- Mathematics and experiments show that light is a transverse wave – the electric and magnetic field vectors point in directions that are perpendicular to the direction of motion of the light wave (and as it turns out, they also rare always perpendicular to each other).
Oct 4, 2024 · Light sources are a type of particle accelerator that produce powerful beams of X-rays, ultra-violet, or infrared light. These beams are similar to how holding an envelope in front of a bright light can reveal something about what’s inside the envelope.
Light is a type of electromagnetic radiation that can be detected by the eye. It travels as a transverse wave. Unlike a sound waves, light waves do not need a medium to pass through, they...
Apr 24, 2017 · Light always takes the shortest path between a source and destination. A line drawn from the source to the destination, perpendicular to the wave-fronts, is called a ray. Far from the source, spherical wave fronts degenerate into a series of parallel lines moving in the direction of the ray.
- Light Sources
- Light Travels Much Faster Than Sound
- Light Can Travel Through Empty Space
- Light Travels in Straight Lines
- Models For Light
Something that produces light is called a light source. There are two main kinds of light sources: Incandescent sources use heat to produce light. Nearly all solids, liquids and gases will start to glow with a dull red colour once they reach a temperature of about 525 °C. At about 2300 °C, the filament in a light bulb will start to produce all of t...
Light travels at a speed of 299,792,458 m/s (that’s nearly 300,000 km/s!). The distance around the Earth is 40,000 km, so in 1 second, light could travel seven and a half times around the world. Sound only travels at about 330 m/s through the air, so light is nearly a million times faster than sound. If lightning flashes 1 kilometre away from you, ...
Unlike sound, which needs a medium (like air or water) to travel through, light can travel in the vacuum of space.
Once light has been produced, it will keep travelling in a straight line until it hits something else. Shadowsare evidence of light travelling in straight lines. An object blocks light so that it can’t reach the surface where we see the shadow. Light fills up all of the space before it hits the object, but the whole region between the object and th...
Light as waves
Rainbows and prisms can split white light up into different colours. Experiments can be used to show that each of these colours has a different wavelength. At the beach, the wavelength of water waves might be measured in metres, but the wavelength of light is measured in nanometres – 10-9(0.000,000,001) of a metre. Red light has a wavelength of nearly 700 nm (that’s 7 ten-thousandths of a millimetre) while violet light is only 400 nm (4 ten-thousandths of a millimetre). Visible light is only...
Light as particles
In 1905, Albert Einstein proposed that light is made of billions of small packets of energy that we now call photons. These photons have no mass, but each photon has a specific amount of energy that depends on its frequency (number of vibrations per second). Each photon still has a wavelength. Shorter wavelength photons have more energy. The photoelectric effect is when light can cause electrons to jump out of a metal. These experiments confirm that light is made of these massless particles c...
A straight line that originates at some point is called a ray. The part of optics dealing with the ray aspect of light is called geometric optics. Light can travel in three ways from a source to another location: (1) directly from the source through empty space; (2) through various media; (3) after being reflected from a mirror.
In all of these cases, light is modeled as traveling in straight lines called rays. Light may change direction when it encounters objects (such as a mirror) or in passing from one material to another (such as in passing from air to glass), but it then continues in a straight line or as a ray.
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May 24, 2024 · When we look at a single point light source, the farther away it is, the flatter the light wavefronts will be when they reach us. When the source is very far away (e.g. the sun), then the wavefronts are essentially flat.
