Physics Unit 3 Test Flashcards
G (giga)
Meaning (Whole numbers or fraction)
1 000 000 000
Meaning (Decimal)
____
Meaning (Scientific notation)
10^9
Meaning (words)
Billion
M (mega)
Meaning (Whole numbers or fraction)
1 000 000
Meaning (Decimal)
____
Meaning (Scientific notation)
10^6
Meaning (words)
Million
k (kilo)
Meaning (Whole numbers or fraction)
1 000
Meaning (Decimal)
____
Meaning (Scientific notation)
10^3
Meaning (words)
Thousand
d (deci)
Meaning (Whole numbers or fraction)
1/10
Meaning (Decimal)
0.1
Meaning (Scientific notation)
10^-1
Meaning (words)
Tenth
c (centi)
Meaning (Whole numbers or fraction)
1/100
Meaning (Decimal)
0.01
Meaning (Scientific notation)
10^-2
Meaning (words)
Hundredth
m (milli)
Meaning (Whole numbers or fraction)
1/1 000
Meaning (Decimal)
0.001
Meaning (Scientific notation)
10^-3
Meaning (words)
Thousandth
μ (micro)
Meaning (Whole numbers or fraction)
1/1 000 000
Meaning (Decimal)
0.000 001
Meaning (Scientific notation)
10^-6
Meaning (words)
Millionth
n (nano)
Meaning (Whole numbers or fraction)
1/1 000 000 000
Meaning (Decimal)
0.000 000 001
Meaning (Scientific notation)
10^-9
Meaning (words)
Billionth
find scientific notation of:
500
5 x 10^2
find scientific notation of:
0.5
5 x 10^-1
find scientific notation of:
0.05
5 x 10^-2
find scientific notation of:
0.005
5 x 10^-3
find scientific notation of:
5 000
5 x 10^3
find scientific notation of:
300 000 000
3 x 10^8
find scientific notation of:
80
8 x 10^1
how many grams in one kg?
1 x 10^3 = 1 000
how many millimeters in one metre?
1 x 10^3 = 1 000
how many microseconds in one second?
1 x 10^6 = 1 000 000
write down the following in km
- 2000 m
- 200 m
- 2 x 10^4
- 2 km
- 0.2 km
- 20 km
write down the following in seconds
- 5 000 ms
- 5 x 10^7 μ
- 5 s
- 50 s
write the following with scientific notation to two significant figures
- 1 500 m
- 1 500 000 m
- 0.15 m
- 0.015 m
- 1.5 x 10^3 m
- 1.5 x 10^6 m
- 1.5 x 10^-1 m
- 1.5 x 10^-2 m
Wave effect
The waves carry energy . There is no flow of water, the wave effect is the result of up and down motion.
Oscillations
The to-and-fro movements.
Transverse waves
the oscillations are at right-angles to the direction of travel.
An example of transverse waves
radio waves
Longitudinal wave
the to-and-fro movements are oscillated with the direction of travel.
Refractions
The section where the waves are bunched up
Compressions.
The section where the waves are stretched out.
An example of longitudinal waves
Sound waves
The Speed of the waves is measured in
Metres per second (m/s)
Frequency is measured in
Hertz (Hz)
For example a frequency of
Four waves passing any point per second means that the frequency is 4 hertz.
The time for one oscillation is called
The period and is equal to
1/frequency
The wavelength is
The distance between any point on a wave and the equivalent point on the next.
The wave equation.
Write the equation in words:
speed = frequency x wavelength
Write the equation in symbols (use these: f , v, 𝞴, = , x )
V =f 𝞴
Write the equation in units:
ms-1 = Hz x m
The amplitude is
The maximum distance a point moves from its rest position when a wave passes.
Wavelength
Speed / Frequency
Frequency
Speed / Wavelength
Electromagnetic waves are
They are transverse waves because the oscillations (vibrations) are at the right-angles to the direction of travel.
a source loses energy
A source loses energy when it radiates electromagnetic waves. A material gains energy when it absorbs them.
speed of waves
All electromagnetic waves travel at the speed of light.
They can travel through a vacuum.
They travel through a vacuum at a speed of 300 000 kilometres per second.
Where do electromagnetic waves come from?
Electromagnetic waves are emitted (sent out) whenever charged particles oscillate or lose energy in some way.
- Greater the energy → Higher the frequency
- Higher the frequency → Shorter the wavelength.
Is emitted by radioactive materials
Gamma waves
Can cause a suntan
Ultraviolet
Is used to transmit TV pictures
Radio waves
Is diffracted around hills.
Radio waves
Is used to look at your luggage
X-ray
Is used to sterilise food
Gamma waves
Is used in a TV remote control
Infrared
Is detectable by the human eye
Visible light
Can cause materials to ‘Fluoresce’
Ultraviolet
Is used in wifi
Microwaves
Heaters produce these waves and we can detect them with our skin, they can also be used to take photographs at night.
Name of wave:
Infrared
Typical wavelength, λ / m:
10^-5 m
Frequency, f / Hz
( f = 300 000 000 / λ)
f = 300 000 000 / 0.00001
= 10^8 /10^-5
=3 x 10^13 Hz
Up to what temperature are infrared waves produced (and not visible light)?
700° C
Beware if you use a sunbed, these waves can make you blind.
Name of wave:
Ultraviolet
Typical wavelength, λ / m:
10^-8 m
Frequency, f / Hz
( f = 300 000 000 / λ)
f = 300 000 000 / 0.00000008
= 10^8 /10^-8
=1 x 10^16 Hz
Why can you use these to sterilise equipment?
sterilizes surfaces by killing microorganisms.
Cooks food and communicates with satellites
Name of wave:
Microwaves
Typical wavelength, λ / m:
10^-2 m
Frequency, f /Hz ( f = 300 000 000 / λ)
f = 300 000 000 / 0.02
= 10^8 /10^-2
=1 x 10^10 Hz
What detector and emitter of these waves might you be carrying?
The detector and emitter of the microwaves is operated through two sensor elements. An antenna and a receiver. The antenna collects the radiation and the receiver measures the electric signal collected
This type of wave is called a ray, be careful it is dangerous, you can use it to check if people’s bones are broken
Name of wave:
X-ray
Typical wavelength, λ / m:
10^-10 m
Frequency, f //Hz
( f = 300 000 000 / λ)
f = 300 000 000 / 0.0000000001
= 10^8 /10^-10
=1 x 10^18 Hz
Why can it be used to look at bones? How does the x-ray behave when it encounters different parts of the body?
Because long wavelengths can pass through flesh but not bone, so the bones show up on x-ray photographs.
X-rays can pass through some parts of the body and so we can see bones without ‘cutting’ the skin.
They pass through skin and flesh but (shown as black areas on the ‘x-ray’) not through bones (shown as white areas on the ‘x-ray’).
Why is it also ‘dangerous’? Explain what it does to be also called ‘dangerous’
Give details of how to reduce the danger.
It damages living cells in the body and can cause cancer or mutations,
- which mean the cells do not do the job they are meant to do.
- When these cells reproduce they create problems, called ‘cancer’.
- To reduce the danger we reduce our exposure to x-rays and shield our bodies with lead (if you work in the x-ray department of a hospital)
Concentrated beams of X-rays can be used to treat cancer by destroying abnormal cells.
With reference to the electromagnetic spectrum and human actions explain why some people might say that ‘mobile phones cook your brain’. Explain both underlined parts of this statement.
Your brain because microwaves are used by mobile phones.
These microwaves produce a heating effect when absorbed.
When the body is exposed to microwaves, they can cause internal heating of body tissue.
In this case, the microwaves from the mobile phone is, ‘cooking’ our brain tissue.
What Are Electromagnetic Waves?
Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. Like other waves, electromagnetic waves transfer energy from one place to another, this is called electromagnetic radiation. Electromagnetic waves can transfer energy through matter or across empty space.
How do microwaves transfer energy inside a microwave oven?
They transfer energy through the air inside the oven to the food.
Magnetic similar to electromagnetic
The magnet exerts magnetic force over an area all around it. This area is called a magnetic field. Because of the field surrounding a magnet, it can exert force on objects without touching them. They just have to be within its magnetic field.
An electric field is similar to a magnetic field. It is an area of electrical force surrounding a positively or negatively charged particle. Like a magnetic field, an electric field can exert force on objects over a distance without actually touching them.
How an Electromagnetic Wave Begins
When an electrically charged particle vibrates.
which causes the electric field surrounding it to vibrate as well.
In turn, creates a vibrating magnetic field.
The two types of vibrating fields combine to create an electromagnetic wave.
Electromagnetic Wave Interactions
When electromagnetic waves strike matter, they may:
reflect, or bounce back from a surface;
refract, or bend when entering a new medium;
diffract, or spread out around obstacles.
The most important source of electromagnetic waves on Earth
is the sun. Many other sources of electromagnetic waves depend on technology.
microwaves
mobile phones, TV and communication satellites, telephone link, Wi-Fi, radar, heating effect used in microwave ovens
Infrared
radiant heaters and grills, TV remote controllers, security alarms, and lamps, light pulses, and optical fibers.
visible light
only type of radiation visible to the eye
ultraviolet
Causes tanning, skin, ginger, and eye damage. Causes fluorescence (makes some chemicals glow) and kills bacteria.
x-ray
Used for x-ray photography, causes fluorescent, causes cancer, but can kill cancer cells
gamma waves
emitted by radioactive materials. Uses an effect as for X rays, used for sterilizing medical equipment and food.
