Overall quick test Flashcards
Give three reasons why geologists didn’t accept Wagner’s theory.
Any three from: he wasn’t a geologist, supporting evidence was limited, it could be explained more simply, the movement of continents wasn’t detectable.
What provides the heat in the Earth’s core?
The decay of radioactive elements
What evidence do scientists study to obtain information about the Earth’s age?
Fossils of plants and animals, and radioactivity of rocks
What type of wave, generated by an earthquake, travels through the liquid outer core of the Earth?
P-waves
In plate movement, old rock is destroyed by which process? (HT)
Subduction
What two factors produce rock stripes of alternating polarity? (HT)
Deep-floor spreading and the changing polarity of the Earth’s magnetic field every million year.
What type of wave is a sound wave?
Longitudinal
A water wave has a frequency of 5 hertz and a wavelength of 0.1m. What is the speed of the wave?
0.5m/s
What is a student describing if they tell you the number of waves produced each second?
Frequency
A station broadcasts signals at a frequency of 30MHz. If the speed of light is 3 x 10 {8} m/s, what is the wavelength? (HT)
10m
What is the difference between moons and asteroids?
Moons orbit planes; asteroids orbit the Sun
What two methods are used to measure the distance of stars?
Relative brightness and parallax
How is the wavelength of light changed if the source of light is moving away?
The wavelength increases (red shift)
Why is it hard to predict the fate of the Universe?
The amount of mass in the Universe is hard to measure
How do spectra give evidence for red shift? (HT)
They’re displaced towards the red end of the spectrum
What is the relationship between the distance of galaxies and the speed at which they’re moving away? (HT)
They’re proportional to one another
Which proton transfers the most energy: infrared or ultraviolet?
Ultraviolet
Name 3 ionising radiations.
Ultraviolet radiation; gamma; x rays
Give 2 ways in which radiation can damage cells.
Any 2 from: the heating effect (sunburn); it can cause ageing of the skin; it can cause mutations; it can cause radiation poisoning
What is the ozone layer?
A thin layer of gas in the Earth’s upper atmosphere that absorbs some of the sun’s harmful ultraviolet radiation
How does the radiation emitted by the Earth compare with that emitted by the Sun? (HT)
The radiation from the Earth has a lower principal frequency
Give 3 reasons why the intensity of a beam of photons decreases the distance.
Some photons are scattered and reflected by other particles; some photons are absorbed by particles; photons spread out as they travel
What change in the Earth’s atmosphere causes global warming?
An increase in the percentage of greenhouse gases, such as carbon dioxide, in the atmosphere
Why is optic fibre useful when sending infrared and light radiation?
They can travel huge distances without becoming significantly
What is noise?
Unwanted frequencies in a signal (random variations)
How is an analogue signal different from a digital one?
Analogue signals can have any value; digital signals only have two (‘1’ or ‘0’)
Why doesn’t noise affect digital signals? (HT)
Even with noise, it’s clear which parts of the signal represent 1 and 0, so it can be regenerated without noise
How is data, collected about the Earth’s changing temperature, used? (HT)
It is used with climate models to look for patterns in the possible causes of global warming
Why is electricity distributed through National Grid at high voltage?
To reduce the energy losses
Name five primary energy sources used to generate electricity.
Any five from: coal; gas;oil; nuclear; wind; water (hydroelectric, tidal, wave); solar; biofuel
The burning of fossil fuels releases carbon dioxide into the atmosphere. What to problems does this contribute to?
Global warming; climate change
How is a voltage induced between the ends of a coil?
By rotating a magnet near the coil
What are the three forms of energy that are involved in a hydroelectric power station?
Potential energy; kinetic energy; electrical energy
How much energy is transferred by a 60W lamp in 3 seconds?
180J
How efficient is an electric motor that uses 400J/s to give 100J/s of useful energy?
25%
An electric fire was left on for 30 minutes and the total energy transferred was 1.5kWh. What is the power rating of the fire? (HT)
3kW
A student plots a speed-time graph. The graph gives a horizontal straight line. What does that tell you about the acceleration?
It was zero - the speed was constant
A man walks North at 2m/s for 10 seconds, then rests for another 20s. What is his displacement? (HT)
20m North
With a rocket, the engine pushes gas backwards. What is the name of that force?
Action
A force of 12N acts on a truck for two seconds. What is the change in momentium?
24kg m/s
Give 3 examples of safety devices used in cars.
Crumple zone; seat belt; air bag
A cyclist of mass 60kg is moving at a speed of 4m/s. How much kinetic energy does the cyclist have?
1/2 (half) x 60 x 4{2} = 480J
A person weighing 800N gains 16,000J of gravitational potential energy as they’re carried up in a lift. How high did they go? (HT)
20m
A person has 800J of kinetic energy. If they have a mass of 100kg, how fast are they travelling? (HT)
4m/s
If a Perspex rod is rubbed with a cloth, it loses electrons. What charge will the rod now have?
Positive
If a battery of 12V is connected across a bulb and a current of 3A flows through it, what is the resistance of the bulb?
4 omega sign thing
How could the relationship between the current and voltage across a component be described if the resistance is constant?
They’re proportional
A 12V batery is connected across a resistor of resistance 24(omega sign thing). What current flows? (HT)
0.5A
Why does a component heat up when a current flows? (HT)
There are more collisions between the flowing electrons and the vibrating ions, giving a higher resistance. This leads to more heat being produced by the resistor
What principle do generators use to generate electricity?
The principle of electromagnetic induction
What is the power of a 12V lamp in a circuit where a 0.5A current flows?
6W
In a transformer, what induces a voltage across the secondary coil?
A changing magnetic field
A transformer has a primary coil of 200 turns. If the transformer changes 12V to 240V, how many turns must be on the secondary coil? (HT)
4000 turns
A 60W light bulb has a 240V power supply connected across it. What current flows? (HT)
0.25A
What particles are found in the nucleus?
Protons and neutrons
Name the three types of ionising radiation.
Alpha;Beta;Gamma
What is the type of radiation that passes through paper but is stopped by 3mm of aluminium?
Beta
Give 2 sources of background radiation.
Any two from: radon gas; medical; food; cosmic rays; gamma rays; nuclear industry
What is meant by the term ‘half-life’?
The time it takes for the radioactivity to halve
Describe an alpha particle? (HT)
An alpha particle is a helium nucleus and consists of 2 protons and two neutrons
A radioactive source has an activity of 288 counts per minute and a half-life of 6 hours. What will the activity be after 24 hours? (HT)
18 counts per minute
If a radioactive nucleus emits a beta particle, how does the nucleus change? (HT)
It has one more proton and one less neutron than the original nucleus
How is intermediate-level waste stored?
It is mixed with concrete and stored in big containers
What particles were used to bombard the gold foil in the Rutherford-Geigar-Marsden experiment?
Alpha particles
What conclusion was made about the nucleus from the Rutherford-Geigar-Marsden experiment?
Gold atoms (and therefore all atoms) consisted of mainly empty space with a small, dense core called the nucleus. The charge on the nucleus was positive.
What element is used in control rods in a nuclear reactor? (HT)
Boron
What elements can be used in a nuclear power station fuel rod? (HT)
Uranium or plutonium
What makes the stars appear to move from east to west?
The rotation of the Earth from west to east
What two angles describe the positions of a star?
The angles of declination and right ascension
What is a lunar eclipse?
When the Earth passes directly between the Sun and the Moon, casting a shadow onto the moon
What is a sidereal day? (HT)
The time taken for the Earth to rotate 360 degrees on its axis
Why don’t eclipses occur every month? (HT)
The Moon doesn’t orbit the Earth in the same plane as the Earth orbits the Sun
What changes when waves cross the boundary between one medium and another and are refracted?
The speed of the wave and the wavelength
What is the power of a lens with a focal length of 0.2m?
power = 1 / 0.2 = 5 dioptres
Why is a mirror usually used in an astronomical telescope?
It can be made larger than a lens and therefore gathers more light. This gives greater detail in the image
A refracting telescope has a magnification of x3. If the focal length of the objective lens is 0.6m, what is the focal length of the eyepiece? (HT)
0.2m
What 2 things does the observed intensity of a star depend on?
Luminosity and the distance from the Earth
What does the brightness of a Cepheid variable depend on?
The frequency/period of the pulses
What did Shapley believe about the Universe?
That the universe contained only one big galaxy
What did Edwin Hubble discover about the Universe by observing Cepheid variable stars in distant galaxies?
That the universe is expanding
A nearby galaxy is 0.88Mpc from Earth. If the Hubble constant is 70kn s{-1} Mpc{-1}, what is the speed of recession? (HT)
distance x hubble constant = speed of recession
- 88Mpc x 70km s{-1} Mpc {-1} = speed of recession
- 6km/s = speed of recession
How can Cepheid variables be used to estimate the star’s luminosity? (HT)
By measuring the frequency of the pulses
What two things does the pressure of a gas depend on?
The number of collisions per second betewen the particles and the walls of the container; the momentum of the particles.
What is the value of absolute zero?
-273 degrees celsius
How is energy transferred from the core of a star to the photosphere?
By convection and photons of radiation
What information can be obtained by examining the Sun’s spectrum?
The elements present in the SUn
What element is mainly present in the core of a star that becomes a supernova?
Iron
In the Hertzsprung-Russell diagram, what two types of star don’t appear in the main sequence?
White dwarfs and red giants (accept red supergiants
The speed of light 3 x 10{8}m/s. How much mass must a star lose to radiate 1.8 x 10{17} joules of energy? (HT)
2kg
