P5.2 Flashcards
(55 cards)
Do these + Check if you understand this first
Describe the difference between a longitudinal and transverse wave
In a longitudinal wave, oscillations occur parallel to the direction of energy transfer.
In a transverse wave, oscillations occur perpendicular to the direction of energy transfer.
What is EM radiation
- light waves
- travels as a wave
Can EM radiation travel in a vacuum
YES
Is EM radiation transverse or longitudinal
Transverse
Do EM waves require particles to travel
NO - that’s why it can travel in a vacuum
What determines the ‘colour’ of a light wave
It’s frequency / wavelength
What do you need to produce any sort of wave
Something must initially oscillate / vibrate
How are sound / mechanical waves created
Are created by vibrating particles
….. Which collide with neighbouring particles…
… transferring kinetic energy
How are EM waves created
Are created by vibrating charged particles!!
… which creates an oscillating electrostatic field.
…. Which creates an oscillating magnetic field
… transferring electromagnetic energy
Define the EM spectrum
A Continuous range of all possible frequencies/ wavelengths of EM radiation
Small wavelengths has…
High frequency’s
Large wavelengths has..
Low frequency’s
As wavelength increases…
Frequency decreases
What is the amplitude of EM radiation
A measure of its light intensity
Types of EM radiation = pneumonic
RADIO MICROWAVE INFRARED VISIBLE ULTRAVIOLET X-RAY GAMMA RAY
What EM radiation has the largest wavelength
Radio waves
What EM radiation has the smallest wavelength
Gamma rays
What EM radiation has the smallest frequency
Radio waves
What EM radiation has the highest frequency
Gamma rays
Low frequency means…
Low energy
Define light intensity
How much light is arriving in a given time over a given area
A distant star explodes and emits red light and gamma rays simultaneously.Explain why gamma rays and red light rays reach the Earth at the same time. (3 marks)
Gamma rays and red light rays are both forms of electromagnetic radiation.
Thus, both travel at the same speed in a given medium.
Hence, they will arrive at the Earth at the same time if emitted simultaneously.
How are radio waves produced - 5 steps
- An oscillating potential difference is applied across a wire.
- Electrons oscillate backwards and forwards at same frequency.
- Produces oscillating electrostatic and magnetic fields.
- These fields travel and cut across an aerial.
- Electrons inside the aerial oscillate, producing anelectrical signal.