waves

Question 1

order of wave spectrum

Answer 1

-radio waves
-microwaves
-infra red
-visible light
-ultra violet
-x-ray
-gamma rays

Question 2

why do objects appear opaque?

Answer 2

they don’t transmit any light

Question 3

define intensity:

Answer 3

power of radiation per unit of area

Question 4

objects that are hotter than their surroundings emit _____ radiation than they absorb

Answer 4

more

Question 5

what type of wave is a sound wave?

Answer 5

longitudinal

Question 6

what is ultrasound?

Answer 6

sounds above 20,000 Hz

Question 7

how are ultrasound used to view internal structures?

Answer 7

-ultrasounds are refracted, some are also reflected at boundaries
-when it is fired at an object, every time it hits a boundary some of the waves are reflected back at us
-if we know the time taken and speed for it to travel, we can work out the distance of these boundaries and produce images

Question 8

properties of p waves:

Answer 8

-longitudinal
-can travel through liquids and solids
-faster than s waves

Question 9

properties of s waves:

Answer 9

-transverse
-only through solids

Question 10

define a transverse wave?

Answer 10

The movement of the particles is at right angles to the direction of the wave.

Question 11

define a longitudinal wave?

Answer 11

movement of the particles is parallel to the direction of the wave.

Question 12

Name a transverse wave

Answer 12

Light, water, mexican wave, all the waves on the electromagnetic spectrum, s-waves

Question 13

longitudinal wave, what is meant by an area of compression, and an area of rarefaction?

Answer 13

compression is where the particles are closest together, rarefaction is where the particles are furthest apart

Question 14

the amplitude of a wave

Answer 14

maximum displacement of the wave away from its undisturbed position

Question 15

What is frequency?

Answer 15

Frequency is the number of waves that pass a point per second

Question 16

period of a wave?

Answer 16

period is the time (number of seconds) it takes for each wave to go by

Question 17

What is rarefraction?

Answer 17

As light moves from a less dense medium to a more dense medium the light bends towards the normal and vice versa

Question 18

what can UV radiation cause to the skin?

Answer 18

sunburn, prolonged exposure can cause skin cancer

Question 19

what waves are used for communication?

Answer 19

radio waves, microwaves, infra red, visible light

Question 20

what is a wave speed?

Answer 20

speed at which the wave moves or energy is passed through a medium

Question 21

how do waves transfer through a solid?

Answer 21

particles vibrate against each other and transfer kinetic energy through the material

Question 22

technique used to detect objects in deep water and measure water depth:

Answer 22

-echo sounding
-high frequency waves emitted, reflected and detected
-time diff betw emission and detection and wave speed used to calc distance

Question 23

what do waves do

Answer 23

transfer energy from one place to another (w/o transfer of matter)

Question 24

long waves travel by

Answer 24

diffracting around the curved surface of earth

Question 25

short waves travel by

Answer 25

reflecting on the ionosphere (electrically charged layer of upper atmosphere)
bounce back and forth repeatedly and cover long distances
can also be bluetooth

Question 26

very short waves travel by

Answer 26

directly from transmitter to receiver
can be obstructed by object

Question 27

speed of Soundwaves in air

Answer 27

330m/s

Question 28

Describe the difference between transverse and longitudinal waves.

Answer 28

transverse wave, the oscillations are perpendicular to the direction of energy transfer

longitudinal wave, the oscillations are parallel to the direction of energy transfer