Radiation and waves

Question 1

define wave

Answer 1

regular disturbance that transfers energy

Question 2

period of wave

Answer 2

number of seconds for one full cycle
1/freq

Question 3

transverse

Answer 3

perpendicular to direction of wave

Question 4

longitudinal

Answer 4

parallel to direction of wave

Question 5

ripple tank

Answer 5

generate waves using power supply attached to dipper
dipper moves up and down at fixed freq

Question 6

oscilloscope

Answer 6

attach signal generator to speaker
start with both mics same distance but move one away
when waves are aligned on display measure distance between mics to find one wavelength

Question 7

refraction

Answer 7

when travelling through diff material, wave change speed
frequency stays same, wavelength decrease slow down vice versa

if wave hits material at angle it change direction (refraction)

Question 8

em spectrum from low to high freq

Answer 8

radiowaves
microwaves
infrared
visible light
ultraviolet
xrays
gamma rays

Question 9

em radiation can be emitted by

Answer 9

changes in nuclei, atoms or molecules
vis ultra and xray emitted when electrons drop energy levels
infrared when bonds in molecules vibrate

Question 10

when em absorbed

Answer 10

ceases to exist becomes heat
high UV, xray, gamma all can cause ionisation
UV from son absorbed by oxygen forming ozone which absord more UV

Question 11

an atom is ionised if

Answer 11

it loses an electron
if loses its positive ion

Question 12

uses of radiowaves

Answer 12

communication

Question 13

uses of microwaves

Answer 13

communications and cooking

Question 14

uses of infrared

Answer 14

increase of monitor temperature

Question 15

uses of light

Answer 15

sight, communication through optical fibres

Question 16

uses of UV

Answer 16

fluorescent lamps

Question 17

uses of xrays

Answer 17

see inside things

Question 18

gamma rays

Answer 18

sterilising things

Question 19

reflection

Answer 19

angle of incidence = angle of reflection
the normal is the line that bisects the middle of the two

Question 20

specular reflection

Answer 20

parallel incident waves reflected in a single direction by smooth surface
causes clear reflection

Question 21

scattered reflection

Answer 21

parallel incident waves reflected by uneven surface
waves are reflected in all directions

Question 22

concave lense

Answer 22

caves inward
causes light to diverge

Question 23

convex lense

Answer 23

caves outward
cause light to converge

Question 24

soundwaves and hearing

Answer 24

eardrum vibrates from particles
vibrations passed on to ossicles
through canal
to the cochlea which turns vibrations into electrical signals for the brain

Question 25

ultrasound

Answer 25

used for medical imaging - reflection of sound when reach a boundary between two different media
used for finding flaws in materials

Question 26

P waves and S waves

Answer 26

P waves longitudinal, travel through solids and liquids, faster than S waves
S waves transverse, travel through solids