UNIQUE SIENE EMY Test (Unit 25) Name :... Paper: Physics ate :... ode: 5054 lass: II Time llowed: 5Minutes Maximum Marks: 25 1 Theory Section: [Total 17 Marks] 1 doctor uses a radioactive isotope, iodine-11, to find the volume of blood in a patient s body. Information about iodine-11 is given in Fig. 1.1. proton (atomic) number 5 nucleon (mass) number 11 radiation emitted beta-particles and gamma-rays Fig. 1.1 (a) (i) escribe the structure of an atom of iodine-11. (ii)...[] The radioactive decay equation below shows an iodine-11 nucleus decaying into a xenon nucleus (Xe). opy the equation and insert the proton number and the nucleon number of the xenon nucleus. 1 5 1 I Xe + β [2] (b) escribe the differences between beta-particles and gamma-rays....[]
2 (c) The doctor uses a sample of iodine-11 that initially produces a count rate of 144 000 per second. The whole sample is injected into the patient s arm. Nine small samples of blood, each of volume 2.0 cm, are taken from the other arm at 2 minute intervals. Fig. 1.2 shows the count rates from the nine samples. sample number 1 2 4 5 6 7 8 9 time after injection / min 2 4 6 8 10 12 14 16 18 count rate / per second 0 4 12 18 28 40 8 6 40 (i) Fig. 1.2 State two reasons why different count rates are obtained from the nine samples.............[2] (ii) alculate the average value of the count rates from the last four samples. This is the average count rate from a volume of 2.0 cm of blood. (iii) average count rate =...[2] Using your answer to (ii), determine the volume of blood in the patient s body, which has a total count rate of 144 000 per second. total volume =... cm [2] (iv) Sample number 9 is kept. The count rate is measured again after 16 days. Estimate the value obtained, given that the half-life of iodine-11 is 8.0 days. count rate =...[2] edicated to My Son Mohammad Irtaza Haider Zain. ode 5054 [Turn over
(d) escribe one precaution that the doctor must take when handling this radioactive source.... 1 2...[1] [Total 17] MQ SETION: [Total 8 Marks] The results of the Geiger-Marsden scattering experiment provided evidence for the presence of the nucleus within the atom. What were scattered in this experiment? alpha-particles beta-particles gamma rays gold nuclei Two types of emission from a radioactive source are separated by passing them through a magnetic field. The deflections are shown in the diagram. beam with two types of emission P magnetic field into page What are the emissions P and Q? Q emission P emission Q alpha-particles gamma-rays beta-particles gamma-rays gamma-rays alpha-particles gamma-rays beta-particles narrow beam of alpha-particles is fired at a thin piece of gold foil. Which is the final direction of the largest number of alpha-particles? gold foil beam of alpha-particles
4 Ra decays with a half-life of 1600 s. Rn decays with a half-life of 52 s. Po decays with a half-life of 9.1 s. Pb decays with a half-life of 10.6 h. 4 The changing count rate for one of these radioactive nuclides is shown in the graph. 70 60 count rate counts per second 50 40 0 20 10 0 0 20 40 60 80 100 120 time / seconds From the half-life shown by the graph, which was the decaying radioactive nuclide? Ra Rn Po Pb
5 5 radioactive source is placed cm from a Geiger-Müller tube in air. The average count rate is 742 counts / minute. source Geiger-Müller tube counter Then, in three experiments, measurements are taken with sheets of different materials placed between the source and the tube. The results are recorded in the table. material of sheet between source and tube thin card aluminium foil thick lead average count rate / counts per minute 27 275 68 Which types of radiation does the source emit? alpha and beta only alpha and gamma only beta and gamma only 6 alpha, beta and gamma etween 1909 and 1911, Geiger and Marsden carried out experiments in which alpha particles were fired at metal foil. Most of the alpha particles passed through the foil with small deflections, but some were deflected through a large angle. These results suggest that atoms contain clouds of electrons through which some alpha particles cannot pass. atoms contain neutrons that alpha particles bounce off. atoms have positive and negative charges spread throughout their volume. atoms have positive charges concentrated in a small volume. 7 Which equation shows a nuclear fission reaction? 2 1 H + 2 1H 4 2 He 14 7 N + neutron 15 7 N 46 21 Sc 46 21Sc + gamma ray 29 92 U 95 8 Sr + 141 54 Xe + neutrons
6 8 student investigates the emission from an unknown radioactive source. The source is 10 cm in front of a detector. strong magnetic field between the source and the detector is then switched on. 10 cm detector radioactive source The results are shown. lead shield air region of magnetic field average count per minute without magnetic field 4500 with magnetic field 2000 background radiation 50 Which radioactive source produced these results? source emissions from source alpha-particles and gamma-rays only beta-particles only beta-particles and gamma-rays only gamma-rays only MQ nswer Sheet 1 5 2 6 7 4 8 edicated to My Son Mohammad Irtaza Haider Zain. ode 5054