WAVES

Question 1

what is wavelength

Answer 1

distance of an entire oscillation

Question 2

what is amplitude

Answer 2

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

Question 3

what is time period

Answer 3

time it takes for one complete oscillation

Question 4

what is frequency

Answer 4

number of waves tht pass a fixed place in a given amount of time

Question 5

what is a transverse wave

Answer 5

oscillation are perpendicular to the direction of energy transfer

Question 6

give examples of transverse waves

Answer 6

light, radio, waves of water

Question 7

what are longitudinal waves?

Answer 7

oscillation is parallel to the direction of energy

Question 8

give examples of longitudinal waves

Answer 8

sound waves and ultrasound waves

Question 9

what do longitudinal waves

Answer 9

compressions and refractions

Question 10

how do you calculate frequency

Answer 10

1/t

Question 11

whats the practical for frequency,wavelength and speed

Answer 11

fill ripple tank with water znd place a vibrating bar inside of it
connect the vibrating bath to a power pack
place a lamp above the ripple tank and a sheet of white paper belkow it
turn on the ripple tank
to find wavelength : measure the distance of 10 wavelengths on the paper and divide it by 10 to find one
freuquency:set a timer and count the number of waves in 10seconds and ivide it by 10 the find the frequceny of one
speed:frequecy x wavelength

Question 12

how do you measure the speed of sound

Answer 12

attach microphone to oscilloscope
clap once next to microphone
sound will echo off the wall and come back to microphone
uise oscilloscope to measure the time it took the travel
total distance/time

Question 13

what happenes in the leslie cube practical

Answer 13

leslie cube with 4 different surfaces
fill leslie cube with hot water
point inferred detector at each surface
keep same distance between lelie cube and detector so measurements are repeatable
the results in order from most to least inferred immersion :matt black shiny black white and shiny matallic

Question 14

what happens when light enters a medium

Answer 14

their speed changes as does their angle as it bends towards the normal

Question 15

in refraction what happens to frquency

Answer 15

stays constant

Question 16

how are the angle of refraction and angle of incidence related

Answer 16

angle of refraction is smaller than the angle of incidence

Question 17

if we dont have a infared detector in the leslie cube practical what should we use and what are the problems with it

Answer 17

use a thermometer with bulb painted black
the problems are that the resolution is lower this is bad because it will not be able to detect large differences between surfaces

Question 18

What are the 4 sides of a Leslie cube

Answer 18

Matt black
Shiny black
White
Shiny metallic

Question 19

What happens to a wave as it slows down when it crosses the boundary

Answer 19

Refracted ray will bend to wards the normal

Question 20

What happens to a wave as it speeds up after crossing the boundary

Answer 20

Refracted away from away from the normal

Question 21

What happens if a wave travels at the right angle to the boundary along the normal

Answer 21

Change their speed but not direction

Question 22

What are used for radio waves and why is it suitable and bad for you

Answer 22

Television and radio signals

Travel long distances through air
Longer wavelengths can bend around obstructions to allow detections of signals

Can penetrate the body

Question 23

What are microwaves used forand why is it suitable and bad for you

Answer 23

Satellite communications and cooking
Pass through atmosphere to reach satellites
Heat food

Penetrate body causing internal heating

Question 24

What is ir used for and why is it suitable and bad for you

Answer 24

Cameras and heating

All hot objects emit heat
Transfer energy quickly

Damage cells

Question 25

What is visible light used for

Answer 25

Fibre optic communication

Shorter wave lengths so can carry more information

Question 26

How is uv used

Answer 26

Energy efficient lights artificial tanning

Chemicals absorb uv and emit light

Question 27

How do x rays work

Answer 27

Fires x rays at a body
Dense materials absorb the X-rays
Pass through lungs and small intestine (air)but partially pass through heart(flesh)
Then gets recorded by a detector plate

Question 28

What happens to X-ray images

Answer 28

Images start off white
Only goes black if an area receives radiation

Question 29

Name two ways to improve the Leslie cube practical

Answer 29

Flasks that are the same shape and size
Sa is the same

Each flask the same distance away from lamp
Intensity of indeed is the same

Question 30

What are gamma rays bad

Answer 30

Ionising radiation causes cancer
Whole body Irritated by gamma rays
Exposed to gamma rays for longer

Question 31

Why does using a high melting point metal good for x rays

Answer 31

Electrons causing heating
Increasing temperature
Allow more electrons to collide per second