What is light?
Light is a form of energy transmitted via packets of electromagnetic radiation in a wave-like motion.
What are photons?
Photons are the packets of radiation in light. They have no charge, no resting mass, and travel at the speed of light.
How fast do light waves travel?
Light waves travel at the speed of light, which is 300,000 km/s.
What is the difference between sound waves and light waves?
Sound waves require a medium to travel and are much slower than light waves, which do not require atoms for radiation.
What are the four transformations of light waves?
The four transformations are emission, absorption, reflection, and refraction.
What is emission?
Emission is when objects emit light and are termed luminous. E.g., Neon signs, incandescent lamps.
What is absorption?
Absorption is the process in which light is absorbed by matter and converted into energy.
What is reflection?
Reflection occurs when light does not match the natural frequency of an atom and bounces off the material.
What is regular reflection?
Regular reflection occurs off a smooth surface, creating a clear image.
What is diffuse reflection?
Diffuse reflection occurs off rough surfaces, scattering light rays in many directions.
What are the characteristics of an image seen in a plane mirror?
The image is upright, the same size as the object, laterally inverted, virtual, and appears as far into the mirror as the object is in front.
What is refraction?
Refraction is the change in direction of light waves when passing from one transparent medium to another.
What is the law of refraction?
When light travels to a denser medium, it refracts towards the normal; when to a less dense medium, it refracts away from the normal.
What is a convex lens?
A convex lens is thicker at the center, bending parallel rays of light to converge at the focal point, producing an inverted, real image.
What is a concave lens?
A concave lens is thinner at the center and thicker at the edges, causing light rays to diverge from a virtual focal point.
What is the focal point of a lens?
The focal point is where light rays parallel to the lens’ principal axis converge or appear to diverge.
What types of images do convex and concave lenses form?
Convex lenses form real, inverted images; concave lenses form virtual, upright images.
What is the application of convex lenses?
Convex lenses are used in magnifying glasses, eyeglasses, cameras, microscopes, telescopes, and projectors.
What is the bionic eye?
The bionic eye captures images and transmits data to a processing unit, which sends signals to a retinal implant.
What are microwaves?
Microwaves have longer wavelengths than visible light and can be absorbed by water, carbohydrates, and fats.
How do mobile phones use microwaves?
Mobile phones encode voice, text, and data into microwaves and exchange waves with cellular towers for communication.
What are X-rays used for?
X-rays are used in radiology to produce images of bones and blood vessels and in radiotherapy to target cancerous cells.
What are gamma rays?
Gamma rays have high energy and short wavelengths, used in PET scans and radiotherapy to target cancerous cells.
