Physics

Define eficiency

The amount of useful output of energy that a system uses from its total energy input.

What is a closed system

A system that does not allow energy in or out of the system.

what is an open system

A system that allows energy in or out of the system.

What is wasted energy (dissipated energy)?

Energy transferred in a not useful way, typically to the surroundings as thermal energy.

Define dissipation

When energy that is not useful to an object, is transferred to the surroundings.

Define an energy source

A supply of energy, that can be used to achieve demand

What is renewable energy?

Energy that can be replenished as it is used (e.g wind, solar power or hydroelectric).

Describe what non-renewable energy is?

A resource of energy that is finite, therefore cannot be replenished as it is used.

State the advantages of nuclear power energy sourcing:

.Infrastructure is already built. It is very cost efficient. It is easy to run due to resources needed being easy to aquire.

Nuclear power stations disadvantages

Releases nuclear waste (bad for human health and wildlife), dangerous for employees to run, release toxic fumes.

Define what density is

Density is the mass per unit of volume.

State the equation to density

Density = Mass / Volume.

What is the equation to work done?

Work done = Force (Newtons) x distance (meters).

What is the word equation for kinetic energy

Kinetic energy = 0.5 x mass (kg) x velocity squared.

What is the equation for gravitational potential energy

Gravitational potential energy = mass x height x gravitational field strength.

What is the word equation to elastic potential energy

Elastic potential energy = 0.5 x spring constant x extension squared.

State the word equation to efficiency

Efficiency = Useful output of energy / Total input of energy.

Define energy dissipation

Energy that is transferred out of a system not usefully, therefore is wasted energy.

Explain conduction

Conduction is when heat energy is transferred through particles to heat (typically) solid. This is done by a heat source transferring energy to particles as heat energy- this is transferred to the kinetic energy stores of the particles. The vibration of the particles increase, which causes them to collide with other neighbouring particles. This then makes the heat energy transfer to the neighbouring particles, in the same way it did between the heat source and the beginning particle.

Define convection

Heat transfiguration that occurs due to the physical movement of particles.

Explain a convection current.

In fluids, a convection current describes when a heat source heats particles nearest to the heat source- making them expand. The decrease in density of particles causes the particles to rise,. Then the particles cooler, denser and further away from the heat source are displaced by the heated particles- as they have risen. These particles then get closer to the heat source, expanding, becoming more dense and rise. At the same time, the previously risen particles cool, condense and sink. This process is then repeated.

Define infrared waves

The transfiguration of heat without the utilization of particles, caused by waves. These waves can travel through vacuums- regions with no particles.

Define the limit of proportionality

The maximum amount of force that can be applied to an elastic object, before it becomes inelastically deformed.

What is elastic deformation?

When an elastic object is deformed, and the limit of proportionality is not exceeded, therefore when the force is removed, the object can return to its original shape.

What is inelastic deformation

When an elastic object has been deformed beyond the limit of proportionality and cannot return to its original shape.

Define the conservation of energy

Energy can be transferred usefully, stored or dissipated, but can never be created or destroyed.

Define thermal Energy

Energy gained by an object when it increases in tempreture.

Define nuclear Energy

energy gained by an object when a chemical reaction is about to take place.

Define kinetic Energy

Increases with movement speed of an object, remains constant when speed is maintained, and decreases when an object slows down.

Define gravitational Potential Energy

Energy gained by an object when it has potential of being overcome by gravity

What is chemical energy?

Energy gained by an object when it is stationary- not moving.

What is elastic potential energy

Energy gained by an object when it is elastically deformed

Equation for work done

W=F x D or work done= force x distance

Kinetic Energy Equation (symbol)

Ek = 0.5 x m x v^2.

State the equation to Gravitational Potential Energy.

Gravitational potential energy= mass x gravitational field strength x height

What is the gravitational field strength of an object

The strength of an objects gravitational field- being the region around an object where when an objects enters it experiences a force called weight; Earth's gravitational field strength is 9.8.

Elastic Potential Energy word Equation

Ee = 0.5 x spring constant x extension^2.

What is elastic Deformation

When an elastic object is deformed, but its limit of proportionality is not exceeded, therefore when the force is removed, the object can return to its original shape.

What is inelastic deformation

When an elastic object it deformed, and the force applied exceeds the limit of proportionality

What is deforming an object?

When you apply force to an object, to change its shape

State the types of Deformation

Includes compressing, stretching, or bending.

What is the process of deformation

When force is applied to an elastic object- this can be done via bending, compressing or stretching.

Define force application

You can only deform something when you apply two or more forces to the object.

Define an electrical field

A region around a charged object, where another charged object experiences a force.

Define electrcity

The microscopic flow of negatively charged particles called electrons through a material.

What are the different forms of radiation?

Gamma rays, beta particles and alpha particles.

What is radioactive decay?

The random process where an atoms unstable nucleus- due to an imbalance of protons and neutrons- expels sub-atomic particles in the form of energy (known as radiation) in order to be stable.

Explain alpha radiation

This type of radiation occurs at random, but when an atom’s nucleus has too fewer neutrons. When an atoms has too fewer neutrons than protons, it will become unstable. To regain stability, the atom emits particles consisting of 2 protons, and 2 neutrons- these particles are called alpha particles. The alpha particles emitted are in the form of an energy called radiation. This causes the relative atomic mass of the atom to decrease, as it looses these protons and neutrons- which are the sub-atomic particles that contribute to the relative atomic mass number of an atom.

What are the type and number of sub-atomic particles in a single alpha particle

2 protons, and 2 neutrons.