Waves Flashcards

Question

How does medium affect the speed of sound?

Answer 1

- As density of medium increases, so does speed of sound. - Sound travels fastest in a solid where the particles are close together (as solids are the most dense) and they can transfer vibrations faster between particles - in gas + liquids, particles are further away (less dense) so vibrations take longer to pass between particles

Answer 2

20-20,000Hz

Answer 3

- prenatal ultrasound scans - crack detection in machinery - breaking kidney stones

Answer 4

- probe emits + receives the waves - ultrasound transmits through the tissue - the waves are reflected whenever there is a change in density to create an image on the screen - the time taken to recieve echo x speed of sound = depth of fetus Which is done multiple times to form image

Answer 5

- the transceiver transmits ultrasound through the metal - waves are reflected back to transceiver when the crack is detected to see how deep in the crack is - time taken and speed through medium is multiplied to find how deep the crack is

Answer 6

Radiowaves, Microwaves, Infrared, Visible, Ultraviolet, X-rays, Gamma rays

Answer 7

- all are transverse - all travel at 3 x 10^8m/s in a vacuum - all can be reflected, refracted and diffracted

Answer 8

- radio + TV signals - long wave radio signals are broadcasted by transceivers and and are reflected by the atmosphere around the world to other transceivers

Answer 9

- cooking wood w large water content + mobile & satellite comms - water molecules in food absorb large amts of microwaves so food gets hot and cooks - are able to transmit though atmosphere to satellites

Answer 10

- cooking food on grills + short range data comms (TV remotes) - thermal energy emits from grill into air and absorbed by food - waves transmit through air from remote, and energy absorbed quickly so are used for short distances

Answer 11

- traffic systems + glasses/ contacts - coloured light transmits through the air and is absorbed by eyes - refraction of light through curved glass is absorbed by eyes to correct vision

Answer 12

- security tagging banknotes, sterilising, tanning - fluorescent ink absorbs UV and reflects white light into eyes - bacteria absorbs UV and is killed - suncream absorbs and/or reflects UV instead of it being absorbed by skin

Answer 13

- airport security scanners, scanning of skeleton - waves are transmitted through bags and picked up by a receiver to form an image - transmitted through body tissue but reflected by bones so the film has a shadow of the bones to identify cracks

Answer 14

- radiotherapy cancer treatment, medical tracer - high energy waves are directed to the cancer which absorbs them and the cells die - patient is injected w radioactive tracer which absorbs gamma so blockages can be seen during a scan

Answer 15

UV, X-rays and gamma rays

Answer 16

have the highest frequency = highest energy which means that they’re more dangerous

Answer 17

- overexposure of ionising radiation causes atoms in cells to lose electrons, ionising them - this can mutate cells and lead to cancer

Answer 18

harms the eyes by damaging the retinas

Answer 19

Burns the skin and tissue

Answer 20

The apparent shift in wavelength when a source moves relative to an observer. As wavelength decreases, frequency increases. The faster the sourceis moving relative to the observer, the more pronounced the difference in pitch and volume.

Answer 21

- as the source gets closer to the observer, there is an apparent increase in frequency which results in a higher volume and pitch, called blue shift - as the source moves away from the observer, there is an apparent decrease in frequency which results in a lower volume and pitch, called red shift