Waves

Question 1

Transverse Waves

Answer 1

Direction of energy propogation is perpendicular to direction of oscillation

Question 2

Transverse Waves Examples

Answer 2

Electromagnetic waves

Question 3

Longditudnal Waves

Answer 3

Direction of energy propogation is parallel to direction of oscillation

Question 4

Longditudnal Wave examples

Answer 4

Soundwaves
Ultrasound

Question 5

Doppler Effect

Answer 5

• Wavespeed is constant
• Wavefronts bunch up
• Wavelength decreases
• Frequency increases
• Wavespeed = Wavelenght x frequency

Question 6

Radiowaves

Answer 6

Broadcasting and communications

Question 7

Microwaves

Answer 7

Cooking and satellite transmissions

Question 8

Infared

Answer 8

Heaters and night vision equipment

Question 9

Visible light

Answer 9

Optical fibreas and photography

Question 10

Ultraviolet

Answer 10

Fluorescent lamps

Question 11

X-rays

Answer 11

Observing internal structure of objects and materials, including medical applications

Question 12

Gamma rays

Answer 12

sterilising food and medical equipment

Question 13

Microwave dangers

Answer 13

Internal heating of body tissue

Question 14

Infared dangers

Answer 14

skin burns

Question 15

Ultraviolet dangers

Answer 15

damage to surface cells and blindness

Question 16

Gamma rays dangers

Answer 16

cell mutations = cancer

Question 17

protective measures against risk of EM waves

Answer 17

• Protective clothing - goggles, gloves
• Suncream, sunglasses, covering skin
• Limit exposure time

Question 18

Critical Angle

Answer 18

Angle of incidence above which total internal reflection occurs

Question 19

Total internal reflection occurs when…

Answer 19

• Angle of incidence is greater than critical angle
• travels froma dense medium to a less dense medium

Question 20

Optical fibre uses

Answer 20

Communication: high speed data transfer
MEdicine: endescopes and inside body flexible cameras

Question 21

Prisms

Answer 21

• Allows us to see objects that are not directly in our sight
• TIR by 90
• Ray travels parrallel to initial path at different height

Question 22

Prism uses

Answer 22

Binoculars

Question 23

Human Hearing

Answer 23

20 - 20,000 Hz

Question 24

Investigate speed of sound in air - outside

Answer 24

• Two people stand a set distance between each other
• Measure distance using a trundel wheel
• Person A holds a stopwatch
• Person B claps
• When person A sees the clap they start the stopwatch
• When person B hear the clap they stop the stopwatch
• Repeat 3 times
• Speed = distance/time

Question 25

Speed of Sound in air

Answer 25

340 m/s

Question 26

Sound waves travel fastest in

Answer 26

solids - more vibrations

Question 27

Sound cannot travel through...

Answer 27

a vaccum

Question 28

investigate the frequency of a sound wave using an oscilloscope

Answer 28

- connect microphone to oscilloscope - create a sound using a speaker - Adjust the time base so that at least one complete wave is on the screen - count the number of divisions for one complete wave - calculate the time period - the number of divisions for one complete wave x time base - Frequency = 1/time

Question 29

Investigate the speed of sound of air - inside

Answer 29

- place two microphones two metres apart, measure using a tape measure - Make a loud noise - bang a hammer on a metal plate - Microphone A will start the ectric timer when it hears noise - Microphone B will stop electric timer when it hears noise - speed = distance/tiem - Repeat five times and calculate and average

Question 30

Higher Pitch

Answer 30

Higher Frequency

Question 31

Higher Loudness

Answer 31

Higher Amplitude

Question 32

change number of waves present on oscilloscope screen

Answer 32

adjust time base