Alpha particles, beta particles and gamma rays. Alpha particles are helium nuclei with a +2 charge, Big, heavy and slow moving, don't penetrate into materials, Very ionising, Blocked by paper.
Beta particles are high-energy electrons with a -1 charge; Quite small, move quite fast, Penetrate materials moderately, Ionise moderately, for every beta particle emitted, a neutron turns into a proton in the nucleus, some are blocked by thin Aluminium, but certainly blocked by tissue.
Gamma rays are electromagnetic waves with shorter wavelength (higher frequency) than x-rays, Opposite to alpha, Penetrate materials well, Weakly ionising, blocked by 7 cm of lead.
The carbon cycle, the flow of carbon on our planet, is amazingly complex. Here's a quick look at how carbon flows between different areas on our earth and how humans have likely contributed to global warming.
A convex mirror is a curved mirror in which the reflective surface bulges toward the light source. Convex mirrors reflect light outwards, therefore they are not used to focus light. Such mirrors always form a virtual image, since the focus (F) and the centre of curvature (2F) are both imaginary points "inside" the mirror, which cannot be reached. Therefore images formed by these mirrors cannot be taken on screen. (As they are inside the mirror)
A collimated (parallel) beam of light diverges (spreads out) after reflection from a convex mirror, since the normal to the surface differs with each spot on the mirror.
The image is always virtual (rays haven't actually passed through the image,their extensions do), diminished (smaller), and upright . These features make convex mirrors very useful: everything appears smaller in the mirror, so they cover a wider field of view than a normal plane mirror does as the image is "compressed". has a reflecting surface that bulges inward (away from the incident light). Concave mirrors reflect light inward to one focal point, therefore they are used to focus light. Unlike convex mirrors, concave mirrors show different image types depending on the distance between the object and the mirror.
These mirrors are called "converging" because they tend to collect light that falls on them, refocusing parallel incoming rays toward a focus. This is because the light is reflected at different angles, since the normal to the surface differs with each spot on the mirror.
In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency. Media having such a property are termed dispersive media. Dispersion is sometimes called chromatic dispersion to emphasize its wavelength-dependent nature, or group-velocity dispersion (GVD) to emphasize the role of the group velocity. The most familiar example of dispersion is probably a rainbow, in which dispersion causes the spatial separation of a white light into components of different wavelengths (different colors). However, dispersion also has an effect in many other circumstances: for example, GVD causes pulses to spread in optical fibers, degrading signals over long distances; also, a cancellation between group-velocity dispersion and nonlinear effects leads to soliton waves. Dispersion is most often described for light waves, but it may occur for any kind of wave that interacts with a medium or passes through an inhomogeneous geometry (e.g. a waveguide), such as sound waves. There are generally two sources of dispersion: material dispersion and waveguide dispersion. Material dispersion comes from a frequency-dependent response of a material to waves. For example, material dispersion leads to undesired chromatic aberration in a lens or the separation of colors in a prism. Waveguide dispersion occurs when the speed of a wave in a waveguide (such as an optical fiber) depends on its frequency for geometric reasons, independent of any frequency dependence of the materials from which it is constructed. More generally, "waveguide" dispersion can occur for waves propagating through any inhomogeneous structure (e.g. a photonic crystal), whether or not the waves are confined to some region. In general, both types of dispersion may be present, although they are not strictly additive. Their combination leads to signal degradation in optical fibers for telecommunications, because the varying delay in arrival time between different components of a signal "smears out" the signal in time.
Inertia is the resistance of any physical object to a change in its state of motion. It is represented numerically by an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to describe the motion of matter and how it is affected by applied forces.
Inertia comes from the Latin word, "iners", meaning idle, or lazy. In common usage, however, people may also use the term "inertia" to refer to an object's "amount of resistance to change in velocity" (which is quantified by its mass), or sometimes to its momentum, depending on the context (e.g. "this object has a lot of inertia"). The term "inertia" is more properly understood as shorthand for "the principle of inertia" as described by Newton in his First Law of Motion. This law, expressed simply, says that an object that is not subject to any net external force moves at a constant velocity. In even simpler terms, inertia means that an object will always continue moving at its current speed and in its current direction until some force causes its speed or direction to change. This would include an object that is not in motion (velocity = zero), which will remain at rest until some force causes it to move.
On the surface of the Earth the nature of inertia is often masked by the effects of friction, which generally tends to decrease the speed of moving objects (often even to the point of rest), and by the acceleration due to gravity. The effects of these two forces misled classical theorists such as Aristotle, who believed that objects would move only as long as force was being applied to them.
Pascal's law or Pascal's principle states that "pressure exerted anywhere in a confined fluid is transmitted equally in all directions throughout the fluid."
The hydraulic brake is an arrangement of braking mechanism which uses brake fluid, typically containing ethylene glycol, to transfer pressure from the controlling unit, which is usually near the operator of the vehicle, to the actual brake mechanism, which is usually at or near the wheel of the vehicle.
The most common arrangement of hydraulic brakes for passenger vehicles, motorcycles, scooters, and mopeds, consists of the following: •A brake pedal or lever •A pushrod, also called an actuating rod •A master cylinder assembly containing:
A piston assembly made up of: Either one or two pistons -A return spring - A series of gaskets/ O-rings - A fluid reservoir - Reinforced hydraulic lines -A brake caliper assembly usually containing: oOne or two hollow aluminum or chrome-plated steel pistons called caliper pistons oA set of thermally conductive brake pads -A rotor (also called a brake disc) or a drum attached to a wheel A glycol-ether based brake fluid usually fills the system (other fluids may also be used) and manages the transfer of force/ energy between the brake lever and the wheel.
At one time, passenger vehicles commonly employed disc brakes on the front wheels and drum brakes on the rear wheels. However, because disc brakes have been shown a better stopping performance and are therefore generally safer and more effective than drum brakes, four-wheel disc brakes have become increasingly popular, replacing drums on all but the most basic vehicles. Many two-wheel vehicles designs, however, continue to employ a drum brake for the rear wheel