chapter 11 - waves 1

Question 1

what is a progressive wave?

Answer 1

an oscillation that can travel through matter, transfer energy from one place to another but not matter

Question 2

what is a transverse wave?

Answer 2

oscillations are perpendicular to the direction of energy transfer

Question 3

what is a longitudinal wave?

Answer 3

oscillations are parallel to the direction of energy transfer

Question 4

what is the wave equation?

Answer 4

wave speed= wave length x frequency
or
wave speed= wavelength/ time

Question 5

define the displacement?

Answer 5

distance from the equilibrium position in a particular direction

Question 6

define amplitude?

Answer 6

maximum displacement from equilibrium position

Question 7

define frequency?

Answer 7

number of wavelengths passing a given point per unit time

Question 8

define wavelength?

Answer 8

minimum distance between two points in phase on adjacent waves

Question 9

define wave speed?

Answer 9

distance travelled by wave per unit time

Question 10

what is the phase difference?

Answer 10

the difference between the displacements of particles on different waves. measured in radians

Question 11

what is the phase difference of an in phase wave?

Answer 11

phase difference of 0

Question 12

what is phase difference of an out of phase wave?

Answer 12

phase difference of pi

Question 13

how can you determine frequency using an oscilloscope

Answer 13

each horizontal square on oscilloscope represents a time interval. this is called time base. each vertical square = p.d from the microphone picking up wave. using the time we can use formula F=1/T

Question 14

define the reflection of a wave?

Answer 14

wave changes direction at a boundary between two different media, remaining in the original medium.

Question 15

state the law of reflection

Answer 15

angle of incidence = angle of reflection

Question 16

what occurs to the frequency and wavelength of a wave that is reflected?

Answer 16

they remain the same

Question 17

define the refraction of a wave?

Answer 17

when a wave changes direction as it changes speed from one medium to another

Question 18

what is partial reflection?

Answer 18

when a wave refracts some is reflected

Question 19

what occurs to the wavelength and frequency of wave when it refracts?

Answer 19

frequency remains the same however wavelength changes. v= frequency x wavelength

Question 20

define diffraction?

Answer 20

when a wave passes through a gap or travel around an obstacle they spread out.

Question 21

what affects diffraction?

Answer 21

the size of the wavelength compared to the size of the gap

Question 22

define polarisation?

Answer 22

particles oscillate along only one direction, wave is confined to only one plane.

Question 23

define the intensity of wave?

Answer 23

radiant power passing through a surface per unit area

Question 24

formula for intensity

Answer 24

I = P/A or P/ 4 X pi X r^2

Question 25

what is the relationship between intensity and amplitude

Answer 25

intensity is proportional to the amplitude^2

Question 26

what are properties of an electromagnetic waves?

Answer 26

they are waves that travel at speed of light in vacuum

can be plane polarised