Waves Flashcards
State one detector of radio waves.
Aerial
What is the difference in the two waves shown below?
The bottom wave has a higher frequency. (Or the top wave has a lower frequency)
What happens to the speed of light as it travels from air into glass?
The speed of light in glass is slower than the speed of light in air.
In the diagram below, where is;
- the normal ?
- the angle of incidence?
- the angle or refraction?
See diagram
What path will the ray of light take as it passes through the glass prism?
Light ray is refracted at air/glass boundary and glass/ air boundary. Both result in a change of direction.
As it enters the block the speed of the light decreases and it changes direction towards the normal.
As it leaves the block the speed of the light increases and it changes direction away from the normal.
State one use for microwave radiation.
- Mobile phone communications
- Used to heat/cook food
- Microwaves in space are used by astronomers to learn about the structure of nearby galaxies, and our own Milky Way
- Microwaves are also used by fixed traffic
- Radar
State one use for radio waves.
- Radio/TV broadcasting
- Aircraft and shipping bands
- Radio waves detected from space are used by astronomers to find out what objects are made from
In the hills you can sometimes pick up a radio signal but not a television signal?
Radio waves are longer wavelengths than television waves.
Radio waves diffract more and can reach the receiver.
State one use for visible light.
- We use light to see!
- Lasers are visible light and are used in Xbox, Playstation, Bluray player, DVD (where the light is reflected from the tiny pits in the disc, and the pattern is detected and translated into sound or data)
- Lasers also used in laser printers
- In aircraft weapon aiming systems.
What happens when white light is shone through a triangular prism as shown?
The light is refracted and produces a spectrum.
What is meant by refraction?
Refraction is the change of speed of light as it enters a different medium - often observed as a change in direction.
What happens to a light ray as it travels from air into glass?
It will slow down and change direction towards the normal.
State one source of radio waves.
- Transmitter
- Stars
What is the shape of a convex lens.
See image
What type of wave is a microwave?
Transverse.
State one source of visible light.
- The Sun
- Light bulbs
- Anything hot enough to glow
State one detector of infrared
- photodiode
- phototransistor
State one detector of X-rays
Photographic film
Describe how to measure the speed of sound using the equipment below.
- Make a loud sound to the left of the first microphone.
- When the sound reaches microphone one it starts the fast timer, when the sound reaches the second microphone this stops the timer.
- Measure the distance between the microphones using a metre stick.
- The speed is calculated from distance between the microphones divided by the time on fast timer.
What is the difference in the two waves shown below?
The top wave has a bigger amplitude and so has more energy.
(Or the bottom wave has a smaller amplitude so has less energy)
What is meant by the amplitude of a wave?
It is the distance from the centre of the wave to the crest or trough.
State one source of gamma radiation
- Stars
- Some radioactive substances (e.g. Cobalt 60)
State one use for X-rays.
- Create images of bones to detect breaks
- Create images of organs for diagnosis
- Security to scan luggage at airports
- Doctors can give patients a “Barium Meal”, which is a drink of Barium Sulphate. This will absorb X-rays, and so the patient’s intestines will show up clearly on a X-Ray image.
State one detector of microwaves.
Aerial
Why does a triangular prism produce a spectrum from white light?
Different frequencies/colours of light refract by different amounts.
You are 5km away from a thunder storm. What reaches you first - the thunder or the lighning? Explain your answer.
The lightning. The speed of light is faster than the speed of sound.
Which wave property is illustrated below?
Wavelength
Which member of the electromagnetic spectrum has the most energy?
Gamma radiation as it has the highest frequency