PAG 06.3 Experiments With Polarisation Flashcards
What is polarisation?
The process of preventing all oscillations except those in a single plane
What types of waves can be polarised?
All transverse waves including all waves in the EM spectrum
Why can sound not be polarised?
Longitudinal waves cannot be polarised since their oscillations are parallel to the direction of energy transfer. Sound is a form of longitudinal wave
What is observed when light is shone through two polarising filters whose planes are perpendicular to each other?
The first filter blocks all oscillations except those in one plane. This plane is perpendicular to the polarising plane of the second filter, and so cannot pass through it. This means no light is visible through the two filters
How can microwaves be polarised?
Use a metal grid
Describe the nature of waves emitted from a microwave transmitter
A microwave transmitter will emit polarised waves, with a wavelength of the order of a few centimetres (~3cm)
How can microwaves be detected?
Use a microwave receiver. This can then be connected to an analogue or digital meter, or to a sound outputter
How will the sound output of the microwave reviewer change as the microwave intensity increases?
The amplitude of the sound will increase, resulting in a louder sound
What safety precautions should be taken when working with microwaves?
Ensure that the microwave intensity does not exceed the maximum safe level. Microwaves with too high a frequency or intensity can cause burning
Suggest an application for a polarising filter
Polarising sunglasses use lenses that polarise the light. This helps to reduce the glare from road surfaces when driving
What safety precautions should be taken when using a lamp?
The bulb and surrounding areas may become very hot. Allow to cool after use, avoid touching the bulb and metal areas, and switch it off when not in use
