# GCSE Physics

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1. distant galaxy A is further away from distant galaxy B . What can you predict about the electromagnetic radiation astronomers detect from these galaxies
electromagnetic radiation from both galaxies will be red shifted ; galaxy A will have a larger red shift than galaxy B
2. the middle  spectrum is is part of a spectrum from a distant galaxy and the top spectrum is part of the spectrum of the sun explain how the position of the dark lines support the idea that the universe is expanding

the shift in dark lines is a Doppler shift towards the longer wavelength , meaning the source of light is moving away from us , which it would do if the universe was expanding and everything was getting further apart
3. If the universe is expanding at a constant rate , explain , why this means a more distant galaxy is moving faster than one that is not so far away
when larger distance expands it will expand more than a smaller distance
4. a burst of radiation from a distant astronomical object was seen with the largest red shift ever recorded . What does this tell you about the object
It is travelling away from us faster than any other known object
5. explain what astronomers mean by red shift and how it provides evidence that the universe is expanding
Red shift is an increase in the observed wavelength of electromagnetic waves from stars and galaxies.This happens because the galaxy is moving away from us. All distant galaxies are moving away, and galaxies that are furthest away are moving the fastest.This can be explained by expansion of the universe , which would mean that everything is moving away from everything else
6. what does the big bang theory state
all matter exploded out from a single point about 14 billion years ago
7. give two pieces of evidence for the big bang theory
• red shift
• CMBR
8. "why was the universe created ?" suggest one reason why scientists cannot answer this question
they will never have enough evidence and cannot do an experiment to find the answer
9. if new data were collected that did not support the big bang theory , what should scientists do
• check the data
• repeat the experiment
• change the theory to take the new evidence into account
10. Explain why the discovery of the CMBR was so important
• The steady theory state theory says that the universe is expanding but has no explanation for the CMBR; the big bang theory states that there should be radiation left over from the
• big bang that by now will be in the microwave region , so finding this evidence was important to supporting the big bang
11. some theories of the universe suggest there was a big crunch before the big bang . Explain whether scientists have any proof of this theory
• 1. they have no evidence because there is
• no way to get evidence of anything before the big bang as that is when time space and matter were created
12. describe CMBR
CMBR is microwave radiation that is present everywhere in the universe and arrives at the earth from all directions
13. explain why CMBR is so important to the big bang theory
The big bang theory states that the universe expanded from a single point and radiation from the explosion will now be in the microwave region and present throughout the universe ; CMBR fits this description and so is strong evidence for the big bang
14. the steady state theory of the universe says that the universe has always existed and as it expands new galazies of stars are formed in the spaces between other galaxies
explain the main differences between the steady state theory and the big bang theory , and why the big bang theory is the one most accepted by most cosmologists today
The big bang theory states that the universe and matter exploded outwards from a single point about 14 billion years ago. In contrast the steady state theory suggests that the Universe always existed and didn’t start from a single point. Radiation from the time of the big bang would now be in the microwave region, and CMBR has been detected. The steady state theory does not explain CMBR , which comes from all directions
15. when a pupil plays her flute in the classroom the window vibrates give a reason for this
the sound waves passing make the air vibrate and the air particles hit the windows making them vibrate
16. what are fuels
a source of energy they can be used to release energy
17. state and explain one situation where it is better to use solar energy , rather than any of the other energy sources , to generate electricity
if we were in a remote area were there isn't enough room for a power station or the population of the island is small it would be best to use solar energy because it is most cost effective to produce energy on a small scale using solar energy
18. the sun is a
star
19. stars occur in groups . Each group of millions of stars is called a
galaxy
20. there are billions of galaxies which together make up our
universe
21. what is meant by red shift
the light has shifted to the red end of the spectrum
22. what does red shift tell us about distant galaxies
they are moving away from us
23. what are the main ideas of the big band theory
the universe began from a single point and there was an explosion that caused matter to expand outwards
24. explain how red shift supports the theory that the Universe began from a very small point
• light shifted to red end of spectrum
• wavelength increases
• galaxy is moving away
25. in a draught evapouration happens
• faster
• evapouration causes cooling
• so the temperature will decrease faster
26. energy companies encourage people to use electricity between midnight and 7am by selling the electricity at a lower cost
suggest why
• supply exceeds demand
• or
• surplus of electricity at night
27. name one type of wave that may be either transverse of longitudinal
• or
• spring
28. when the door is open , the person can hear the sound but cannot sea the television
explain why
• sound waves will diffract , light doesnt
• the door mych be similar to the sound or the door must be much bigger than light
29. a plane mirror produces a
virtul and upright image
30. suggest why control groups are used
to compare
31. what are the advanatges of using a large sample size
it means there is enough data to give the relationship
32. an increase in energy prices will ...... the payback time for the solar water heater
decrease
33. giving examples explain why electricity is essential for both improving public health and for modern communications
• electricity can be transformed into useful energy such as heat and light
• in public health it is used in fridges for food safety
• it is also used in communication
34. explain why a liquid cools down as it evapourates
• only the fastest molecules have enough energy to escape
• when they escape the av. speed or remaining molecules decreases
• the lower the speed the lower the temp

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 Author: ghoran ID: 159315 Filename: GCSE Physics Updated: 2012-06-19 17:11:23 Tags: waves Folders: Description: revision Show Answers:

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