Science- Waves and Energy

Term 2

What is absolute zero?

The lowest possible temperature, -273 C

What does Absorption mean?

The process of absorption means that a substance catches and transforms energy.

What does amplitude mean?

The height of a wave as measured from the highest point on the wave (peak crest) to the lowest point on the wave (trough)

What is the angle of incidence?

The angle an incoming ray makes with the normal.

What is the angle of reflection?

The angle a reflected ray makes with the normal.

What is the angle of refraction?

The angle a refracted ray makes with the normal.

What does compression mean?

A region of high pressure in which particles are closer together.

What is a concave lens?

A lens that curves inwards.

What is a convex lens?

A lens that bulges outwards.

What is conduction?

A method of heat transfer in which heat is passed by vibration of particles.

What is a conductor?

A substance that allows heat to flow through it.

What is convection?

Transfer of heat in a liquid or gas due to less dense warmer matter rising and denser cooler matter falling.

What is a crest or peak?

The top of the wave. The highest point of the wave.

What is a decibel (dB)?

Unit used to measure loudness

What is an echo?

A sound that is reflected and heard a second time.

Examples of electromagnetic waves.

Radio and television waves, microwaves, infrared rays, visible light, ultraviolet light, x-rays and gamma rays.

What is a frequency?

The number of waves passing a point every second.

What is a gamma ray?

They are a form of electromagnetic radiation (EMR). They are the similar to X-rays, distinguished only by the fact that they are emitted from an excited nucleus.

What is a hertz (Hz)

The unit used to measure frequency.

What is an incident ray?

Incoming ray.

What is an insulator?

A material that does not conduct heat or electricity well

What is the law of reflection?

States that light is reflected at the same angle that it is incident, or i=r.

What is a longitudinal wave?

A wave in which the vibration is the same direction as its travelling.

What is a luminous?

An object that releases or emits light

What is a normal?

An imaginary line that is drawn at right angles to a surface that light is incident upon.

What is an oscilloscope?

A laboratory instrument commonly used to display and analyse the waveform of electronic signals.

What is a plane mirror?

A flat mirror.

What is a period?

The time it takes for two successive crests (one wavelength) to pass a specified point.

What is radiation?

A movement of heat in the form of electromagnetic waves, which can travel through a vacuum.

What is rarefaction?

A region of low pressure in which particles are far apart.

What is a real image?

An image formed when rays of light actually meet.

What is reflection?

Involves a change in direction of waves when they bounce off a barrier.

What is refraction?

The bending of light as it passes from one substance into another substance.

What is a refractive index?

A measure of how easily light travels through a substance.

What is a sound wave?

regions of high and low pressure or originating from a vibrating object and transmitted through a medium.

What is temperature?

A measure of the average kinetic energy of particles in a substance that results in how hot or cold that substance is

What is a thermometer?

An instrument used to measure temperature.

What is total internal reflection?

One light is completely reflected from the boundary of two substances. It occurs when the angle of incident is greater than the critical angle.

What is a transverse wave?

A wave in which the vibration is at right angles to the direction the wave is travelling.

What is a trough?

The bottom of the wave. The lowest point of a wave.

What is Ultraviolet light?

Ultraviolet light has showed a wavelength than visible light. Although UV waves are invisible to the eye, some insects such as bumblebees can see them.

What is a virtual image?

An image formed in which the rays of light do not actually meet, but only appear to meet at a point inside the mirror.

What is visible light?

Light or visible light refers to the visible region of the electromagnetic spectrum – that is the range of wave lengths that trigger brightness and colour perception of humans. It lies between UV and infrared radiation. The human eye can detect wavelength from 380 to 700 nanometers.

What is a wave?

A wave is a regular repeated disturbance of space time. There are two different types of waves; electromagnetic waves which can travel through vacuums; and mechanical ways which require a medium or substance capable of energy transfer to propagate.

What is a wavelength?

The distance from one peak of a wave to the next.

What are X-rays?

X-rays are a form of electromagnetic radiation similar to visible light. Unlike light however x-rays have higher energy and can pass through most objects including the body. Medical x-rays are used to generate images of tissues structures inside the body.

What is energy?

The capacity to do work.

What is the law of conservation of energy?

States that energy cannot be created or restored. Energy can only be transformed from one form into another.

What are the different types of energy?

Potential, elastic, electrical, chemical, nuclear, kinetic, heat, and light.

What is heat energy?

The result of the movement of atoms in solid liquids and gases. Heat energy can be transferred from one object to another. This energy that contained with a matter is known as thermal or heat energy.

What does the transfer of heat energy mean?

Transfer of heat energy is what energy is transferred from a particle with high energy to a particle with lower energy.

Which direction is heat transferred?

The direction is always from a high energy particle to a particle with lower energy.

Can heat be transferred within a substance?

Yes. it stops when all the particles have the same energy level.

What are the three ways that heat can be transferred?

Conduction, through solids, convection, through liquids and gases, and radiation, through space.

What is the process of convection?

It happens when the gas or liquid moves and carries heat with it. When the flute fluid is heated expands. This means that will become less than the cruel fluid around it. Because of this the warmer fluid will try to float over the colder fluid and this is why it will rise.

What are different examples of radiation?

Ultraviolet from the sun, heat from a stove burner, visible light from a candle.

What wave is this?

Transverse wave.

What wave is this?

longitudinal wave.

What is the symbol of a wave length?

λ, measured in metres or centimetres.

What is the symbol for amplitude?

A, measured in centimetres or metres.

What is the symbol for a period of a wave?

T, measured in seconds.

What is the symbol for velocity of a wave?

V

What is the formula to calculate frequency?

Wave length/ speed

What is the formula to determine the speed (velocity) of a wave?

Frequency x wave length

What are the different examples of electromagnetic waves?

Gamma rays, X-rays, Ultraviolet light, visible light (rainbow), infrared radiation (heat), microwaves, radio waves.

What are some examples of mechanical waves?

Sound, water, earthquake waves.

What are the two types of mechanical waves?

Longitudinal and transverse.

An image seen in a plane mirror is…

1. Upright

2. The same size as the object

3. laterally inverted

4. Virtual

5. Appears to be located as far inside the mirror as the object is in front

What is the bending of light called?

Refraction

When does light refract?

When it travels from one transparent substance into another

Why does refraction occur?

Light travels at different speeds through different substances. The differences in its speed result in different amount of bending, or refraction as light passes from one substances to another.

What is the refractive index?

A measure of how easily light travels through a substance. The smaller the refractive index, the faster light travel will travel through a material and vice versa.

What is a critical angle?

When light is refracted so far from the normal that it runs along the boundary of the two substances.

What is total internal reflection?

When any angles of incidence grater than critical angles have no refracted ray. The light is reflected from the boundary as though it was a mirror.

What is light?

Light is a form of electromagnetic radiation. It travels as a wave. It is both a wave and a particle. It has a electric field and a magnetic field.

How do waves behave?

They can be absorbed, so the energy is transferred to the atoms of the object. It can be reflected off it so the wave bounces back off the object. It can be transmitted or pass through as object. This means the waves are bent.

What is luminous?

An object that produces or releases or emits light.

What does the amount of refraction depend on?

The wavelength of the light

The angle of incidence of the light hitting the surface

The density of the medium

What is an optical fibre?

A flexible and transparent fibre made of extruded glass or plastic. An optical fibre works like a light pipe to transmit light between two ends of the fibre.

What are lenses?

Two types of lenses; convex and concave.

Transparent piece of plastic glass or jelly that is curved outwards or inwards.

It helps to focus images for the eye.

What do convex lenses do?

They cause light rays to come together or converge. Is used to magnify. It focuses light to a point called the focus (F). This is called a real image.

What do concave lenses do?

They cause light to diverge or spread out. They spread parallel light rays as though the rays have come from a point behind the lens. they produce images that are smaller, upright and virtual.

What does convergent mean

Converging

What does divergent mean

Different

How does the angle of incidence affect the angle of refraction?

The angle of incidence equals the angle of reflection.

What is the Sclera?

Tough, opaque tissue that extends around the eye and gives the eye its white colour

What is the cornea?

Clear layer at the front and centre of the eye, located in front of the iris

What is the function of the Cornea?

Helps you see by focusing light and keeps out harmful substances

What is the pupil?

Central opening of iris

What is the iris?

Ring shaped tissue, coloured part of the eye.

What is the function of the Iris?

Controls the amount of light that enters the eye with two muscle fibres. Constricts pupil in bright light and dilates in dark.

What is the Retina?

Consists of a specialised layer of rods and cone cells.

What is the function of the retina?

Converts light signals into nerve signal then send these signals to the optic nerve.

Rods- low light situations

Cones- Allows you to see colour.

What is the function of the optic nerve?

Caries the nerve signals to the brain

What is the function of the lens?

Focuses the rays of light onto the retina

What is the function of the pupil?

Centre opening in the iris that allows light to pass through the eye to the retina

What does Hyperopia mean? (Long sightedness)

Cannot focus at short distances, corrected with converging lenses

What does Myopia mean? (Short sigtedness)

Cannot focus at long distances, can be corrected with diverging lenses.

What are the primary colours?

Red, blue, green.