Physics 102 Midterm 04W

Physics 102 Midterm 04W - L First Letter Last Name Physics...

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Unformatted text preview: L First Letter Last Name Physics 102 04W Mid-term 1 Time 50 minutes Student’s Name: Student Number: This exam consists of 5 pages plus a formula sheet. Special Instructions 1. Simple scientific calculator — no graphing calculators 2.} Use the backs of the pages for rough work 3. Clearly show all your work 4. Use pen, papers written in pencil will not be accepted for re-grading 04W NF“ 1 Question 1 (5 marks) Consider the following two reactions, where a proton or a neutron is removed from a nucleus of sodium — 23 a) fiNa + energyenge + proton 3 b) lea + energy—fiNa + neutron Given the following masses: Atomic Masses: Na—23, 22.989770u : Ne-22, 21.991386u : Na-22, 21.994437u me = 0.000549u; mp = 1.007276u; mgHm = 1.007825; m” =1.008665u Determine the energy (MeV) required to remove: i) a proton fist—M FLA) ii) a neutron \a‘U‘l no} iii) Is the proton or neutron more tightly bound in the sodium-23 nucleus? Explain! Question 2 (4 marks) A radioactive sample of sodium-24 (half—life 15 hours) is mixed into a closed water system. The sample’s initial activity is 1.6x104 Bq. i) How many sodium-24 nuclei are in the sample? [‘ XKOR ii) What should be the sample activity 30 hours later? OHOMLS’ {3V iii) After 30 hours a 100 m1 sample of water is taken from the water system and its activity is 2.0 Bq, what is-the volume of the water system? QOXUDH my 04w MT] ' 7. Question 3 a (2 marks) A certain nucleus after absorbing a neutron emits a [3‘ and then splits into two alpha particles. The A, Z of the original nucleus must have been: i) 6, 2 ii) 6, 3 iii) 7, 2 iv) 7, 3 V) 8, 4 ® Question 3 b (3 marks) The figure shows two separate metal spheres. Each sphere has the same positive charge, q. Points 1 and 4 are the same radial distance from the centre of their respective sphere, so are points 2 and 5 and also points 3 and 6. Rank the points 1-6 according to their potential, greatest first, with the potential taken to be zero at an infinite distance away from the spheres. Greatest Smallest V i 7 V'L 04W MTl ’% Question 4 (5 marks) The diagram shows a region of space where there is a uniform electric field of 40 i N/C. The grid has a scale of 1.0 m per box and the electric potential at the origin is +40 V. You are asked to identify the points (A, B, C, D or E) where different quantities are the greatest or least. If the quantity is the same at all points then clearly state this. 3' 9"? i) Electric Potential Reason: ii) Electric Field Greatest ‘ Least Reason: iii) Electric Potential Energy of a negative charge Greatest Q- Least 1 3 42\ Q 36”!“ iv) If akégfiive ghahggis released at A, will it move towards B or D? Explain! v) When it reaches B or D, what is its‘kinetic energy? 04w MN 4 Question 5 (6 marks) i) For each of the following diagrams draw an arrow indicating the direction of the net electric field (due to the point charges) at each of the positions indicated by the dots. If the net field is zero then label it as E = 0. All point charges have the same magnitude. ,0 ' @———-—»--—© it; a 4K? a'_i‘?i_..__f°f@ ® _________ G a) ' b) ii) For figure b) if the magnitude of each charge is q and the length of the edge of the square is 1.0 m. Calculate the net electric field at point P. l 4Jt80 Report your answer in unit vector form and in terms of q and k = 04w Mn 5 c = 3.00 ><108 m/s NA : 6.02 x 1023mole'1 [6] = 1.602 ><10‘19 C me = 000054858 u mp = 1.007276 u mn = 1.008665 11 1 u : 1.661 ><10‘27 kg 1 u = 931.5 MeV/c2 E=(Am)c2 %’¥=——/\N T1/2: 11:3 NZN06-A1 16:71:32?“ quE E=4mor212 <I>E=fE-dA VB—VA=— fE-dl=V—qufl AV:Ed : q 41rcor Q=CV C_&o.é .7 = 71qu R = pi p = p011 + 01(T - To)1 P = Bi? a - b = (szX + ayby + azbz = abcosfl a x b = (czbe — azby)'i + ((2sz — axbz)j + (ax?)y -— aybx) la la >< bl = absinfi g=9.8m/s2 vzvo—i—at ac : xo+vot+%at2 v22v3+2a($—$0) k =1/(47r60)= 8.99 ><109 N ~1112/C2 co = 8.85 x 10‘12 F/m or CQ/(N-mQ) pg 2 47r X 10"7 H/m or T-m/A quva F=il><B u=iAN T=p><B IB(7")=%‘:—i F=poglfil B=poni ngfB‘dA £_.—N9(%B N<I>B=Li L=Iuon21A 82—0de 1: %(1—€_Rt/L) UB=§Li2 MFR; fB-dA=0 fE-dl=—d%(fB-dA) f B ’ : #Oiencl + [1060??? ...
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This note was uploaded on 04/18/2008 for the course PHYSICS 102 taught by Professor Axen during the Fall '02 term at UBC.

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Physics 102 Midterm 04W - L First Letter Last Name Physics...

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