1. D 11. D 21. D 2. B 12. C 22. A 3. C 13. C 23. B 4. C 14. B 24. E 5. C 15. D 25. B 6. A 16. C 26. C 7. D 17. A 27. A 8. D 18. B 28. D 9. D 19. A 29. D 10.E 20. A 30. E 31. The displacement(s) is equal to the total area(A1+A1) under the graph. s = A1+A1 s = ut +(v-u)t/2 Note that from the definition of acceleration : a = (v-u)/t =>(v-u)= at Substitute this into the expression above. s = ut + att/2 s = ut + at2/2 as required. 32. Density of air = Mass of air released/Volume of air released r = Mair/Vair Mair = (363.86-362.00)g = 1.86g = 1.86x10-3kg Vair = 1687.00cm3 = 1687.00x10-6m3 r = 1.86x10-3kg/1687.00x10-6m3 r = 1.1025kg/m3 33.a. T(K) = T(oC) + 273 T(K) = -196 + 273 T(K) = 77K b. The kelvin temperature is directly proportional to the kinetic energy of particles. At 0K particles have no kinetic energy. A lower energy state/temperature, is therefore, not possible. 34.a. Vinverting input = 0V b. I = V/R V = 0.5V R = 10,000W I = 0.5/10000 I = 50mA 35. l = v/f l = 340/1000 l = 0.34m Path difference = (1.37-1.20)m = 0.17m This means that loudspeaker 2 is a distance of 0.17m further away from the microphone than loudspeaker 1. This is a distance equivalent to l/2. Therefore, the waves reach the microphone 180o out of phase and interfere destructively, reducing the amplitude of the sound. 36.a. All metals and carbon are conductors. Plastic and rubber are examples of insulators. Group IV elements such as silicon are semiconductors. b. By adding pentavalent (group V) atoms to group IV semiconductor, n-type semiconductor material is made. This material has a lower resistance than pure semiconductor, as a result of an excess of negative charge carriers in the structure. 37.a. When two atoms join, or fuse together, to produce a single atom of greater mass the reaction is called fusion. b. The mass of the product of a fusion reaction is less than that of the initial reactants. This "missing mass" is converted into energy. E = mc2 Where: m = missing mass c = speed of light
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