P1

Question 1

What are waves?

Answer 1

• A regular disturbance that transfers energy
• The amplitude- displacement from the rest position to a peak or trough
• The wavelength is the distnace between the same two adjacent disturbances(one full cycle of the wave)
• Frequency - number of complete wavaes made by a source-hz(1 wave per second)
• Period- the number of seconds it takes for one full cycle to pass a certain point - period= 1/frequency

Question 2

What are transverse waves?

Answer 2

• The disturbance of the medium is perpendicular(at 90 degrees) to the direction of wave travel
• Electromagnetic and s waves are transverse

Question 3

What are longituidinal waves?

Answer 3

• The disturbance of the medium is parellel to the direction of wave travel
• sound waves and p waves are longitudinal
• They squash up and stretch out the arrangement of particles in the medium they pass through making compressions and rarefractions

Question 4

What are longituidinal waves?

Answer 4

• The disturbance of the medium is parellel to the direction of wave travel
• sound waves and p waves are longitudinal
• They squash up and stretch out the arrangement of particles in the medium they pass through making compressions and rarefractions

Question 5

What is the wavespeed equation?

Answer 5

Wavespeed(m/s)=Frequency(Hz) x Wavelength(m)

Question 6

What is reflection?

Answer 6

• When a wave is sent back to way it comes
• Angle of incidence=Angle of reflection

Question 7

What is refraction?

Answer 7

• When a wave hits a boundary at an angles, but there is a change of speed when this happens and causes a change in direction

Question 8

What is the electromagnetic spectrum?

Answer 8

• A spectrum of 7 waves:Radio, microwaves, infrared,visible, ultraviolet, x-ray, gamma
• Radio has the largest wavelength and gamma has the smallest
• Frequency and energy are highest at the bottom of the list and lowest at the top of the list
• Ultraviolet, xray and gamma rays are the only ionising waves on the spectrum

Question 9

What are Radio waves used for?

Answer 9

• They are used for communication

Question 10

What are microwaves used for?

Answer 10

• Cooking and communication
• The waves penetrate into the food before being absorbed and transferring energy to th water molecules to heat up the food

Question 11

What is infra red radiation used for?

Answer 11

• It can be used to increase or monitor temperature
• Given off by all objects

Question 12

What are visible light rays used for?

Answer 12

It is used to help humans be able to see things, and communication using optical fibres

Question 13

What are ultraviolet waves used for?

Answer 13

Used in fluorescent lamps

Question 14

What are x rays used for?

Answer 14

Help us view internal structures of objects structures and bodies

Question 15

What are gamma rays used for?

Answer 15

Used to help sterilize medical instruments and food

Question 16

What are the two different types of lenses?

Answer 16

Concave and convex lenses

Question 17

What is a concave lense?

Answer 17

• A lens that caves inwards, causes parallel rays of lights to diverge
• Used in glasses of shortsighted people

Question 18

What are convex lenses?

Answer 18

• A lense that buldges inwards and cauases parrallel light rays to converge
• Used in the glasses of long sighted people

Question 19

What are sound waves?

Answer 19

• A wave that transmitts sound that causes objects to vibrate
• Vibrations pass through the surrounding medium as a series of compressions and rarefractions

Question 20

How do we hear sound in our eardrums?

Answer 20

1)Sound waves reach your eardrums and cause them to vibrate
2)These vibrations are passed onto tiny bones in the ear called ossicles through the semi-circular canal and to the cochlea
3)The cochlea turns these vibrations into electrical signals which get sent to your brain
4)The brain interpretes the signals as sounds of different pitches and volumes, depending on frequency and intensity

Question 21

What is ultrasound?

Answer 21

• This is sound with frequencies higher than 20, 000Hz
• Above range of human hearing
• Used in medical and industrial imaging like scanning foetuses

Question 22

What are s waves?

Answer 22

• They are transverse waves that travel at 60% of the speed of p waves
• Can only travel through solids

Question 23

What are p waves?

Answer 23

• They are a really fast type of longitudinal wave that can travel through solids and liquids
• Faster than s waves

Question 24

What is absorbing radiation?

Answer 24

• The balance between emitting and absorbing radiation will affect an objects temperature
• When an object is hotter than its surroundings more radiation is emitted than absorbed-will warm up surroundings
• When object is cooler than surrounding less energy emitted than absorbed-surroundings will cool down
• If an object absorbs and emitts the same amount of energy the temperature stays the same

Question 25

What is intensity?

Answer 25

The power of radiation per unit area