P6-Waves Flashcards by Ben Taylor-Rose

What do waves do?

They transfer energy without transferring matter

How well did you know this?

Not at all

Perfectly

What are the 2 types of waves? (Not longitudinal and transverse)

Mechanical waves (such as sound, water and seismic waves) and Electromagnetic waves (all forms of light waves).

How well did you know this?

Not at all

Perfectly

What is the rest position?

The undisturbed position of particles or fields when they aren’t vibrating

How well did you know this?

Not at all

Perfectly

What is displacement?

The distance that a certain point in the medium has moved from its rest position

How well did you know this?

Not at all

Perfectly

What is the peak?

The highest point above the rest position

How well did you know this?

Not at all

Perfectly

What is the trough?

The lowest point below the rest position

How well did you know this?

Not at all

Perfectly

What is the amplitude?

The maximum displacement of a point of a wave from its rest position

How well did you know this?

Not at all

Perfectly

What is the wavelength?

The distance covered by a full cycle of the wave, usually measured from peak to peak/trough to trough

How well did you know this?

Not at all

Perfectly

What is wave period?

The time taken for a full cycle of the wave, usually measured from peak to peak, or trough to trough

How well did you know this?

Not at all

Perfectly

What is wave frequency?

The number of waves passing a point each second

How well did you know this?

Not at all

Perfectly

What is the formula linking wave period and frequency?

Period = 1/Frequency
T=1/f

How well did you know this?

Not at all

Perfectly

What is wave period measured in?

Seconds
s

How well did you know this?

Not at all

Perfectly

What is wave frequency measured in?

hertz
Hz

How well did you know this?

Not at all

Perfectly

What is the formula linking wave speed, frequency and wavelength?

Wave speed = Frequency x Wavelength
v=fλ

How well did you know this?

Not at all

Perfectly

What is wave speed measured in?

metres per second
m/s

How well did you know this?

Not at all

Perfectly

What is wavelength measured in?

metres
m

How well did you know this?

Not at all

Perfectly

What are the characteristics of longitudinal waves?

Oscillations are in parallel with the wave direction
A medium is needed for waves to move
Examples are sound and seismic waves
They have compressions and rarefractions

How well did you know this?

Not at all

Perfectly

What are the characteristics of transverse waves?

Oscillations are perpendicular to the wave direction
No medium is needed for waves to move
Examples are electromagnetic and water waves
They have peaks and troughs

How well did you know this?

Not at all

Perfectly

What is the law of reflection?

The angle between the incident and normal is the angle between the normal and reflected

How well did you know this?

Not at all

Perfectly

What is the angle of incidence?

The angle between the incident ray and normal

How well did you know this?

Not at all

Perfectly

What is the angle of reflection?

The angle between the reflected ray and the normal

How well did you know this?

Not at all

Perfectly

What is the normal line?

An imaginary line perpendicular to the reflective surface?

How well did you know this?

Not at all

Perfectly

How are mirrors drawn?

With a straight line on the side that reflects and diagonal lines on the other side

How well did you know this?

Not at all

Perfectly

What are the virtual rays drawn with?

Dotted lines

How well did you know this?

Not at all

Perfectly

What is reflection from a smooth flat suface called?

Specular reflection

What is reflection from a rough surface called?

Diffuse reflection

What is an image in a mirror?

Upright, Laterally inverted and virtual

What is refraction?

The direction of a wave as it crosses the boundary between 2 media in which the wave travels at different speeds.

What are wave fronts?

Lines that represent the position of different waves

Where does light refract when it enters a more dense medium?

Towards the normal

Where does light refract when it enters a less dense medium?

Away from the normal

What is the order of the elecromangnetic spectrum from the longest to the shortest wavelength?

* Radio waves * Microwaves * Infrared waves * Visible light * Ultraviolet rays * X-rays * Gamma rays

What is the speed of electromagnetic waves?

300 million m/s

How does energy change down the electromagnetic series?

It increases

What can radio waves penetrate through?

Anything but the ionosphere

What can microwaves penetrate through?

Anything

What can infrared rays pass through?

Most things though stopped by most solids apart from glass

What can visible light pass through?

Anything apart from opaque objects

What can ultraviolet waves pass through?

Everything apart from solids and the ozone layer

What can x-rays pass through?

Anything apart from high density solids e.g. bone and metal

What can gamma rays pass through?

Anything

What rays heat up objects?

Radio waves, Micro waves and Infrared waves

What rays ionise objects?

Ultraviolet rays, X rays and Gamma rays

Radio waves: What are they used for and what are their dangers?

* Used to transmit radio/television programs over large distances * None known

Microwaves: What are they used for and what are their dangers?

* Used to cook food by heating up water molecules as well as transmitting signals between satellites and mobile phones * Can cause heating of bodily tissues

Infrared waves: What are they used for and what are their dangers?

* Night vision, Security systems, Remote controls * Heating absorbed by the skin causing burns

Visible light: What is it used for and what are their dangers?

* Seeing, Cameras, Fire optic communications * No dangers

Ultraviolet waves: What are they used for and what are their dangers?

* Used in sunbeds, security coding and detecting forged bank notes * Skin cancer, damage to eyesight

X-rays: What are they used for and what are their dangers?

* X-ray machines * May lead to cancer

Gamma rays: What are they used for and what are their dangers?

* Used for sterilising medical equipment * High doses can kill cells

For a concave lense where is the focal point?

Behind the lens (a virtual focus)

Outside 2F: Where is the image position, is it magnified/diminuished, is it upright/inverted, is it real/virtual?

* Between F and 2F * Diminuished * Inverted * Real

At 2F: Where is the image position, is it magnified/diminuished, is it upright/inverted, is it real/virtual?

* 2F * N/A * Inverted * Real

Between F and 2F: Where is the image position, is it magnified/diminuished, is it upright/inverted, is it real/virtual?

* Outside 2F * Magnified * Inverted * Real

At F: Where is the image position, is it magnified/diminuished, is it upright/inverted, is it real/virtual?

* No image * N/A * N/A * N/A

Inside F: Where is the image position, is it magnified/diminuished, is it upright/inverted, is it real/virtual?

* Anywhere * Magnified * Upright * Virtual

What does the colour on a surface depend on?

The wavelengths of light the pigments absorb.

What does a translucent object do to light?

Scatters and refracts it

What is the range of human hearing?

20-20000 Hz

What are the uses of ultrasound?

* Breaking kidney stones * Cleaning jewellery * Images of unborn babies

What are the 2 types of seismic waves?

Primary (P-waves) and Secondary (S-waves)

What are the properties of P waves?

* Longitudinal wave * Fast relative speed * Can travel through solids and liquids

What are the properties of S waves?

* Transverse wave * Slow relative speed * Can travel through solids only

What colours emit the most infrared radiation starting from the most?

* Matt black * Shiny black * Matt white * Shiny silver

What is the cube called in the black body practical?

The Leslie cube

What happens to the peak intensity of radiation as the temperature increases?

The peak intensity moves to shorter wavelengths

What is a perfect black body?

An object that absorbs and re-emits all radiation that is incident on it-it doesn't reflect any radiation

How are radio waves created?

* Produced by oscillation in electric circuits-transmitter * When they are absorbed by a reciever, they create an alternating current * The electrical current has the same frequency of the radio waves * Displayed by oscilloscopes

What are the three types of radio waves?

* Long wave * Short wave * Very short wave