Assessment 2 2019 Flashcards
What do waves do?
Waves transfer energy and information from one point to another through vibrations
What is the word and symbol equation for wavespeed?
Wavespeed=Frequency X Wavelength
V= Fx(lamda)
What is a transverse wave?
A wave in which the vibrations are perpendicular to the direction in which the wave travels
What is a progressive
A disturbance moving from a source to surrounding places as a result of which energy is transferred from one point to another.
Give 3 examples of transverse waves
- Water waves
- Secondary earthquake waves
- All 7 regions of the EM spectrum
What is a longitudinal wave?
A wave which the vibrations are parallel to the direction in which the wave travels.
Give 3 examples of longitudinal waves
- Sound waves
- Ultrasound waves
- Primary Earthquake waves
Give 3 applications of echoes
- Measuring the depth of water from a ship
- Measuring to presence of fish beneath a fishing ship
- Measuring the speed of a driver using a speed gun.
What is sound produced by?
Vibrations
What does sound need to pass through?
A medium
What is the range of frequencies that can be heard by a human ear?
20Hz-20,000Hz
What is a sound with a frequency of above 20,000Hz called?
Ultrasound
Give two uses of ultrasound
Can be used to measure the foetal head diameter
Ultrasound can be used in industry to detect defects in metal
What is the electromagnetic spectrum?
The electromagnetic waves are grouped into types that have similar wavelengths and so have similar properties.
What are the properties of a mechanical wave?
Produced by a disturbance in a material medium
Made up of matter
What are the properties EM (Electromagetic Wave)?
Made up for transverse waves
Made up of electric and magnetic fields
A wave produced by a disturbance in the form of a varying electric and magnetic field.
What speed does EM waves travel at?
300,000,000 M/s
What are the similarities of EM Waves?
They can all travel in a vacuum
They are all transverse waves
They all travel at the speed of light (300,000,000 M/s) in a vacuum
What are the seven uses of Em waves
Radio waves-Bluetooth and radios in cars
Microwaves-Heating food and mobile phones
IR(infrared)-Sensors on cars for reversing
Visible light- Seeing things
UV-Detecting forged bank notes
X-ray- Detecting broken bones and fractures
Gamma- Used in medical imagine such as pet scans
What are the five dangers of Electromagnetic (Em) radiation?
Microwave cause internal heating of body tissues
Infrared radiation is felt as heat and causes skin burns
Certain wavelengths of ultraviolet can damage skin cells and leas to cancer
Intense visible light can damage eyes
X rays and gamma rays damage cells, which may lead to cancer
What are the four characteristics of the image formed by a plane mirror?
Same size
Same distance behind the mirror as the object is in front of the mirror
The image is virtual-(can not be projected by on to a screen)
The image is laterally inverted
What is refraction?
The bending of light
What are the two requirements for refractions
Must pass from one medium to another
Angle of incidence must be greater than 0 degrees
What is Amplitude
The greatest displacement of the wave from its undisturbed positions. Unit-Metres
