Radiation and the Universe C Questions Name: Madeley High School Q. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. Explain briefly how stars like the Sun are thought to have been formed.......... (Total 2 marks) Q2. The diagram represents an atom of beryllium. (a) Complete the following statements by writing one of the letters, J, K or L, in each box. Each letter should be used only once. The particle with a positive charge is The particle with the smallest mass is The particle with no charge is (2) (b) Give the reason why all atoms have a total charge of zero....... () (c) Complete the following sentence. There are several isotopes of beryllium. Atoms of different beryllium isotopes will have different numbers of... () (d) What happens to the structure of an atom to change it into an ion?...... () (Total 5 marks) Page
Q3. In the early part of the 20 th century some scientists investigated the paths taken by positively charged alpha particles into and out of a very thin piece of gold foil. The diagram shows the paths of three alpha particles. Explain the different paths A, B and C of the alpha particles. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words................ (3) (Total 3 marks) Q4. (a) The graph shows how the count rate from a sample containing the radioactive substance cobalt-60 changes with time. (i) What is the range of the count rate shown on the graph? From... counts per second to... counts per second. () Page 2
How many years does it take for the count rate to fall from 200 counts per second to 00 counts per second? Time =... years () (iii) What is the half-life of cobalt-60? Half-life =... years () (b) The gamma radiation emitted from a source of cobalt-60 can be used to kill the bacteria on fresh, cooked and frozen foods. Killing the bacteria reduces the risk of food poisoning. The diagram shows how a conveyor belt can be used to move food past a cobalt-60 source. (i) Which one of the following gives a way of increasing the amount of gamma radiation the food receives? Put a tick ( ) in the box next to your answer. Increase the temperature of the cobalt-60 source. Make the conveyor belt move more slowly Move the cobalt-60 source away from the conveyor belt () To protect people from the harmful effects of the gamma radiation, the cobalt-60 source has thick metal shielding. Which one of the following metals should be used? Aluminium copper lead () (Total 5 marks) Page 3
Q5. (a) A doctor uses the radioactive isotope technetium-99 to find out if a patient s kidneys are working correctly. The doctor injects a small amount of technetium-99 into the patient s bloodstream. Technetium-99 emits gamma radiation. Give two reasons why an isotope that emits gamma radiation is injected into the patient rather than an isotope that emits alpha radiation....... 2...... (2) (b) If the patient s kidneys are working correctly, the technetium-99 will pass from the bloodstream into the kidneys and then into the patient s urine. Detectors are used to measure the radiation emitted from the kidneys. The level of radiation emitted from each kidney is recorded on a graph. (i) How do the graphs show that technetium-99 is passing from the bloodstream into each kidney? () Page 4
Madeley High School By looking at the graphs, the doctor is able to tell if there is a problem with the patient s kidneys. Which one of the following statements is correct? Put a tick ( ) in the box next to your answer. Only the right kidney is working correctly. Only the left kidney is working correctly. Both kidneys are working correctly. Explain the reason for your answer. (3) (c) The patient was worried about having a radioactive isotope injected into their body. The doctor explained that the risk to the patient s health was very small as technetium-99 has a short half-life. (i) What does the term half-life mean? () Explain why it is important that the doctor uses an isotope with a short half-life rather than an isotope with a long half-life. (2) (Total 9 marks) Page 5
Q6. The pie chart shows the sources of the background radiation and the radiation doses that the average person in the UK is exposed to in one year. Radiation dose is measured in millisieverts (msv). (a) (i) What is the total radiation dose that the average person in the UK receives? Total radiation dose =... msv () A student looked at the pie chart and then wrote down three statements. Which one of the following statements is a correct conclusion from this data? Put a tick ( ) in the box next to your answer. In the future, more people will be exposed to a greater proportion of radon gas. People that have never had an X-ray get 50% of their radiation dose from radon gas The radiation dose from natural sources is much greater than from artificial sources () (b) The concentration of radon gas inside a home can vary from day to day. In some homes, the level can build up to produce a significant health risk. It is estimated that each year 000 to 2000 people die because of the effects of radiation from radon gas. (i) It is not possible to give an exact figure for the number of deaths caused by the effects of radiation from radon gas. Why? () Page 6
The table gives data for the radiation levels measured in homes in 4 different parts of the UK. The radiation levels were measured using two detectors, one in the living room and one in the bedroom. The measurements were taken over 3 months. Area of the UK Number of homes in the area Number of homes in the sample Average radiation level in Bq/m 3 Maximum radiation level in Bq/m 3 A 590 000 60 5 8 B 484 000 30 8 92 C 22 000 68 000 62 0 000 D 38 000 35 300 95 6 900 Give one reason why the measurements were taken over 3 months using detectors in different rooms. () (iii) Use information from the table to suggest why a much higher proportion of homes were sampled in areas C and D than in areas A and B. (2) (Total 6 marks) Page 7
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Radiation and the Universe C Questions Mark scheme Madeley High School M. The answer to this question requires ideas in good English in a sensible order with correct use of scientific terms. Quality of written communication should be considered in crediting points in the mark scheme. Maximum of mark if ideas not well expressed any two from: dust and gas or remnants of a super nova accept hydrogen for dust and gas do not accept hydrogen burns pulled together by (force of) gravity nuclear fusion starts although candidates may include more detail these points are essential to score the credit [2] M2. (a) L J K all 3 in correct order = 2 marks or 2 correct = mark (b) number of electrons = number of protons accept amount for number (c) neutrons this answer only (d) loses / gains electron(s) [5] M3. correct use of terms underlined in B or C describes 3 tracks correctly for 2 marks describes 2 or track correctly for mark A alpha particle passes straight through the empty space of the atom or it is a long way from the nucleus B alpha particle deflected / repelled / repulsed by the (positive) nucleus C alpha particle heading straight for the nucleus is deflected / repelled / repulsed backwards do not accept hits the nucleus do not accept answers referring to refraction do not accept answers in terms of reflected backwards unless qualified in terms of repulsion mention of difference in charge on nucleus negates that track max 2 [3] Page 9
M4. (a) (i) 200 to 50 accept either order 5.3 accept values between 5.2 and 5.4 inclusive (iii) 5.3 accept values between 5.2 and 5.4 inclusive Or their (a) (b) (i) Make the conveyor belt move more slowly lead (c) Exposure increased the content of some types of vitamin. [6] M5. (a) gamma will pass through the body it refers to gamma oralpha will not pass through the body answers must relate to the body accept skin for body gamma is only slightly ionising accept gamma causes less damage to cells / tissue or alpha is heavily ionising do not accept gamma causes no damage to cells less harmful is insufficient (b) (i) (both graphs show an initial) increase in count-rate accept both show an increase only the right kidney is working correctly any two from: if incorrect box chosen maximum of mark can be awarded reference to named kidney can be inferred from the tick box count-rate / level / line for right kidney decreases (rapidly) it decreases is insufficient Page 0
count-rate / level / line for left kidney does not change it does not change is insufficient Madeley High School radiation is being passed out / into urine - if referring to right kidney radiation is not being passed out - if referring to the left kidney 2 (c) (i) time taken for number of nuclei to halve or time taken for the count-rate to halve short half-life the level of radiation (in the body) decreases rapidly it refers to short life isotope to a safe / very small levelora long half-life the radiation remains in the body / for a long time level of radiation remains high answers in terms of damage eg cancer are insufficient [9] M6. (a) (i) 2.5 The radiation dose from natural sources is much greater than from artificial sources. (b) (i) other factors may be involved accept a specific suggestion eg they may be exposed to other types of radiation accept cannot be sure (in many cases) that the cause of death is radon (poisoning) Page
any one from: different concentrations in different rooms to average out daily fluctuations accept to find an average accept to make the result (more) reliable / valid do not accept to make more accurate on its own (iii) average level (much) higher (in C and D) accept converse some homes have very high level (in C and D) accept maximum level in A and B is low ormaximum level in some homes (in C and D) is very high accept higher radiation levels (in C and D) for mark [6] Page 2