Topic 1- Waves And Optics Flashcards
If a rock were to drop into a pond with a duck siting in it, would the duck move with the wave?
No it would not, the rock transfers energy from it to the duck
What is a wave a transfer of?
Energy
What is the equation for distance involving speed and time?
Distance (d) = speed (v) x time (t)
What is the experiment used to determine the speed of sound, which involves two microphones and an electronic timer
Two microphones are placed a distance apart from each other. An electronic timer is connected to both of these.
A loud sound is made, when this sound reaches microphone A the electronic timer starts. When it reaches microphone B the electronic timer stops.
Then using the distance between the microphones and the time on the electronic timer we can determine the speed of the sound.
What is the speed of radio, electronic signals and light in air?
3x108 m/s
three times ten to the power of 8 metres per second/ 300 million m/s
Why will light reach your eyes almost instantly?
It’s speed is so fast
Tell me the comparison between the speed of light and the speed of sound?
The speed of light (3x10 8 m/s) is MUCH faster than the speed of sound (340 m/s) which is MUCH slower.
What is the equation involving velocity, displacement and time?
Displacement (s) = velocity (v) x time (t)
What is the speed of sound in air?
340 m/s
What is frequency?
The number of waves that pass a point in 1 second
What is frequency measured in?
Hertz (Hz)
What is meant by the wavelength?
The horizontal distance between two adjacent crests or troughs. ( the distance from one point on a wave to the same point on the next)
What is the units of wavelength?
Metres (m)
What is meant by amplitude?
The size from the crest or trough of a wave to the zero line / zero position
What is amplitude measured in?
Metres (m)
If the waves are smaller, what does that mean the amplitude is?
The amplitude is low
If the size of the wave is large what does that mean the amplitude is?
The amplitude is high
If there are a lot of waves that means the frequency is?
The frequency is high
Of there are not a lot of waves that means the frequency is?
The frequency will be low
What is meant by the period?
The period is the time it takes for a wave to pass a certain point
What is the units for period?
Seconds (s)
What is speed?
The distance travelled by a subject per unit time
True or False?
A longitudinal wave is one in which the particles making up the wave vibrate in a parallel motion to the direction the wave is travelling?
TRUE
Which way dot he particles move in a longitudinal wave?
Back and forth
Give an example of a longitudinal wave?
Sound waves
In a transverse wave do the particles making up the wave vibrate perpendicularly or parallel to the direction of the wave?
Perpendicularly
Give an example of a transverse wave?
Radio waves
What is the calculation involving speed, wavelength and frequency of a wave?
Speed (v) = frequency (f) x wavelength (lambda)
What is the order of the members in the electromagnetic spectrum?
Gamma (girls) X-rays (xilaphobic) Ultra-violet (understand) Visible light (Volkswagens) Infrared (in) Microwaves (men) TV and Radio waves (rude)
Can light be reflected?
Yes, light can be reflected
What is the relationship between the angle of incidence and the angle of reflection?
Angle of incidence = angle of reflection
State the principle of reversibility of a ray path
If the direction of a ray of light is reversed it will follow the same path but in the opposite direction.
What are cute bed reflectors used for?
To increase the power of a received signal from a satellite or other source
What is the focus on a curved reflector?
The point where the curves shape collects the signals into one place
Why is the detector of a curved reflector placed at the focus?
So the detector receives a powerful signal
In a transmitting curves reflector where is the source if the signal placed?
The focal point (the focus)
When the signal is reflected in a transmitting curves reflector what are the beams of signal?
The beams of signal produces will be parallel
What is an example of an application of curved reflectors used in telecommunication?
3 satellites in space, placed along the equator.
TRUE OR FALSE?
The satellites above the earth continuously move
FALSE
They are geostationary, meaning they stay above the same position in the Earth’s surface
What is total internal reflection?
When the angle of in essence is bigger than the critical angle, no light escapes; all light is reflected back into the Perspex.
What is meant by the critical angle?
When the angle of incidence is 42° and some light escapes at 90° to the normal line. This is called the critical angle.
What is an optic fibre?
A thin thread like piece of glass along which light can travel.
TRUE OR FALSE
Each optic fibre is about the thickness of a human hair.
TRUE
each optic fibre is about the thickness of a human hair
Why are optic fibres coated with a thin layer of cladding?
To prevent any light escaping or passing through the sides to another fibre in the bundle
What is meant by the refraction of light?
Refraction is the change in speed and sometimes (when angle of incidence is not equal to 0°) direction of a wave due to a change in its transmutation medium
Explain what happens when a ray of light passes through glass
When a ray of light passes from air into glass, it slows down and refracts towards the normal line. As light passes from glass to site it speeds up and refracts away from the normal line.
What is the calculation involving power and focal length?
Power= 1
Focal length(f)
Focal length= 1
Power(p)What is the unit of power?
A dioptre (D)
What is the unit of focal length?
Metre (m)
TRUE OR FALSE
A converging lens has a negative power
FALSE
A converging lens has a positive power
TRUE OR FALSE
A diverging lens has a negative power
TRUE
A diverging lens has a negative power
What can and can’t short sighted people see
CAN:
Near objects
CAN NOT:
Far away objects
What can an can’t lob sighted people see?
CAN:
Far away objects
CAN NOT:
Near objects
TRUE OR FALSE
If someone has short sightedness the image is focused in front of the retina
TRUE
TRUE OR FALSE
Is someone has long sightedness the image is focused behind the retina
TRUE
Where is an image ideally supposed to focus inside the eye?
The retina
What type of lens can cured far sightedness?
A convex lens
What type of lens can cure short sightedness?
A concave lens
