Q1. The diagram below shows the range of wavelengths and frequencies for all the types of radiation in the electromagnetic spectrum.

Transcription

1 Q. The diagram below shows the range of wavelengths and frequencies for all the types of radiation in the electromagnetic spectrum. X-rays, which have frequencies in the range Hz are already marked on the diagram. Complete the diagram by adding the following: (a) (c) (d) (e) gamma radiation, which has shorter wavelengths than X-rays; radio waves which have wavelengths longer than 0.m; the visible spectrum which has wavelengths from 400 nm (violet) to 700 nm (red); ultraviolet radiation (i.e. radiation with a higher frequency than violet light); microwaves which have a shorter wavelength than radio waves and infrared radiation which has a higher frequency than microwaves; (f) an FM radio programme on 92MHz. (Show this with an arrow ) (Total 7 marks) Page of 5

2 Q2. Microwave ovens can be used to heat many types of food. Describe, in as much detail as you can, how microwaves heat food (ii) Microwaves have a frequency of million Hz. Their wavelength is 0.03 m. Calculate the speed of microwaves. Show clearly how you work out your answer Speed of microwaves... m/s (Total 4 marks) ## (a) The wavelengths of four different types of electromagnetic wave, including visible light waves, are given in the table. Type of wave Visible light A B C Wavelength mm. km 00 mm 0.8 mm Which of the waves, A, B or C, is an infra red wave?... () Page 2 of 5

3 A TV station broadcasts at khz. The waves travel through the air at m/s. Use the equation in the box to calculate the wavelength of the waves broadcast by this station. wave speed = frequency wavelength Show clearly how you work out your answer. Wavelength =... m (c) What happens when a metal aerial absorbs radio waves? (d) Stars emit all types of electromagnetic waves. Telescopes that monitor X-rays are mounted on satellites in space. Why would an X-ray telescope based on Earth not be able to detect X-rays emitted from distant stars? () (Total 6 marks) Q4. (a) Scientific research carried out in 3 countries has tried to find out if there are any links between using a mobile phone and developing different types of cancer. About people, half with cancer and half in good health, were interviewed about their mobile phone use. Suggest why people in good health were interviewed. () Page 3 of 5

4 (ii) Interviewing people gave the researchers a large sample size. Give one advantage, in any research project, of having a large sample size rather than a small sample size. () The following information was included in a newspaper article about the research project. It may be difficult to prove there is a link simply by asking people how much they use a mobile phone. People s memories are not always accurate. Scientists in Israel found that people who use a mobile phone a lot are 50% more likely to develop a cancer on the salivary gland just in front of the ears. The cost of the research, 20 million, has been partly paid for by mobile phone companies. No children were included in the research. Draw a ring around the correct answer to complete the following sentence. Using children in scientific research raises environmental ethical social issues. () (ii) Suggest two reasons why some people are concerned that the research was partly paid for by mobile phone companies. Page 4 of 5

5 (iii) In Germany, mobile phones that emit very low levels of radiation are marked with a special symbol. Explain why low emission mobile phones should be marked in this way. (Total 7 marks) Q5. The diagram represents part of the electromagnetic spectrum. Visible light travels through air at m/s. Why can we assume that radio waves travel through air at the same speed as light? () (ii) A radio station broadcasts at a frequency of 200 khz. Use the following equation to calculate the wavelength of the waves broadcast by this radio station. Show clearly how you work out your answer. wave speed = frequency wavelength Wavelength =. m Page 5 of 5

6 (iii) Draw a vertical line on the diagram above to show the position of this radio wave in the electromagnetic spectrum. () (Total 4 marks) Q6. (a) The new Tetra communications system to be used by the police transmits digital signals using microwaves of wavelength 75 cm. Use the following equation to calculate the frequency of the microwaves used by the Tetra system. Show clearly how you work out your answer. wave speed = frequency wavelength Frequency =... hertz Read the following extract from a newspaper and then answer the questions that follow. Residents of Stag Hill Court, a luxury block of flats, are shocked at the plans to site a mobile phone mast on the roof of the flats. They oppose the mast on health grounds, quoting research in Germany that has found a possible increase in cases of cancer around mobile phone masts. A spokesperson for the telecoms company said, The residents should not worry. The research carried out by our own scientists has found no link between ill health and mobile phone masts. This has not reassured the residents, who argue that new independent research is urgently needed. Explain why living near a mobile phone mast could cause ill health. (3) Page 6 of 5

7 (ii) Suggest two reasons why the residents have not been reassured by the research carried out by the telecoms company (Total 7 marks) Q7. The visible part of the electromagnetic spectrum from a star includes a dark line. This line is at a specific wavelength. The diagram shows the position of the dark line in the spectrum from the Sun and in the spectrum from a distant galaxy. (a) Explain how the spectrum shift of the dark line supports the theory that the Universe began from a very small initial point (3) Page 7 of 5

8 Name one other piece of evidence that supports the theory that the Universe began from a very small initial point.... () (Total 4 marks) Q8. The steady state theory was once a popular alternative to the big bang theory. The steady state theory suggested that the universe, although expanding, had no origin and it has always existed. As the universe expands, a small amount of matter is created to keep the universe looking exactly the same all of the time. (a) When considering the origin of the universe, what is the difference between the big bang theory and the steady state theory? The light from distant galaxies shows a red-shift. What is red-shift? () (ii) Why does red-shift provide evidence to support both the big-bang theory and the steady state theory? (c) The steady state theory was important in encouraging new research into the universe. Suggest a reason why scientists were keen to carry out new research. () Page 8 of 5

9 (d) Scientists can answer many questions about the universe, but not the question: Why was the universe created? Suggest a reason why this question cannot be answered by scientists. () (Total 7 marks) Page 9 of 5

10 M. (a) gamma rays above x-rays for mark (c) upper radio wave boundary correct (0 - m) (± mm) for mark visible radiation/light within the middle third of a wavelength band in the correct wavelength range ( m) each for mark (d) (e) (f) ultraviolet between *visible radiation and X-rays for mark microwaves above *radio waves and below *infra red (*not necessarily immediately) for mark between 0 8 Hz Hz and nearer to 0 8 Hz than to 0 7 Hz gains mark [7] M2. absorbed by water / water heated hot water heats (rest of) food / idea of particle vibration (ii) / correct answer with no working = 2 allow mark for s = f x w or correct working i.e., 0000 (000000) 0.03 N.B. correct answer from incorrectly recalled relationship / substitution = 0 2 [4] M3. (a) C or 0.8 mm 0.6 m allow mark for correct transformation and substitution allow mark for changing frequency to Hz answer 600 gains mark 2 Page 0 of 5

11 (c) creates an alternating current accept ac for alternating current accept alternating voltage with the same frequency as the radio wave accept signal for radio wave or it gets hotter (d) X-rays cannot penetrate the atmosphere accept atmosphere stops X-rays do not accept atmosphere in the way or X-rays are absorbed (by the atmosphere) before reaching Earth ignore explanations [6] M4. (a) to compare mobile phone usage between the two groups (ii) enough data to indicate relationships or reduce effect of anomalous data ethical (ii) research may be biased (in favour of companies) negative effects on health may not get published accept negative effects on health may be played down (iii) it allows people to easily identify lower risk phones and this allows people to make a more informed choice accept and this allows a comparison to be made [7] Page of 5

12 M5. all electromagnetic waves travel at the same speed through a vacuum, (so assume same speed in air) accept all parts of spectrum for electromagnetic waves (ii) 500 (m) allow mark for correct transformation and substitution allow mark for using Hz answers = mark 2 (iii) line drawn at correct position anywhere between 000 and next section (0 000) accept their value for (a)(ii) drawn in the correct position [4] M6. (a) or correct equivalent allow mark for correct transformation and substitution (of 75) answer gains mark only 2 any mention of alpha, beta, gamma waves scores 0 marks emit / uses / transmit / receive microwaves accept radiation for microwaves throughout ignore radio waves some microwave / energy absorbed by / enters the body ecf for their given electromagnetic wave do not accept goes through the body raises temperature of (body) cells / tissue / water accept reference to water molecules vibrating faster accept it could cause mutation / harm / kill cells do not accept answers in terms of ionisation ignore references to cancer Page 2 of 5

13 (ii) any two from: research (may be) biased or may have been misled in the past accept not independent or may be lying some research suggests a link long-term effect not proven / studied accept not studied for long enough residents may not have seen the research 2 [7] M7. (a) the observed wavelength of the dark line from the distant galaxy has increased therefore the distant galaxy must be moving away from the Earth suggesting the Universe is expanding outwards from a small initial point existence of cosmic microwave background radiation accept existence of CMBR [4] M8. (a) big bang theory universe started at one point (then expanded) steady state theory universe has no origin / has always existed accept an answer in terms of mass eg steady state theory mass is created wavelength (of light) increases accept answers in terms of frequency decrease accept wavelength stretched but not wave stretched or wavelength / light moves to red end of spectrum do not accept galaxy moves to the red end of the spectrum do not accept light becomes red / redder Page 3 of 5

14 (ii) red-shift is evidence / supports idea of expanding universe accept prove for support both theories use the idea / accept / explain why the universe is expanding (c) to find evidence to support one or both theories accept prove for support accept to gain more knowledge about the universe or to find evidence to disprove one or both theories (d) answer involves (religious) belief accept it cannot be tested or no / insufficient evidence [7] Page 4 of 5

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