CAPE Physics Unit 2 · 2006 · Paper 2

49 questions and parts from this paper. Open one to see it in full, then practise it on Quelpr and get it marked against the mark scheme.

1. 1(a)2 marksExplain how energy is stored in the capacitor when the switch is connected to P.
2. 1(b)(i)4 marksWhen the switch is connected to Q, discharge occurs following I = I_0 e^{-\frac{t}{RC}}. Use data from the discharge graph to complete Table 1 and plot a graph of \ln I against t on the provided grid.
3. 1(b)(ii)1 markWhat is the equation of this new graph?
4. 1(c)(i)1 markFind the gradient of the graph you have drawn.
5. 1(c)(ii)2 marksGiven that R = 47\text{ k}\Omega, deduce the capacitance of the capacitor C.
6. 2(a)4 marksUse the data in Table 2 to plot the transfer characteristic (V_{\text{out}} versus V_{\text{in}}) of the amplifier on the graph sheet provided.
7. 2(b)2 marksDetermine the gradient of the linear region of the graph.
8. 2(c)(i)2 marksIf R_1 is 10\text{ k}\Omega, what is the resistance of R_2?
9. 2(c)(ii)2 marksWhat is the largest positive input voltage which can be used if the amplifier is not saturated?
10. 3(a)(i)2 marksHow much charge is on the drop of mass 3.9 \times 10^{-15}\text{ kg} when it is held stationary by a p.d. of 200\text{ V} between plates 10\text{ mm} apart?
11. 3(a)(ii)1 markHow could the charge on this drop be changed?
12. 3(a)(iii)1 markTo hold the drop stationary when the charge changes the p.d. must be adjusted. Draw a diagram of a circuit which could be connected to P and Q to achieve this, assuming that a power supply with a fixed output of…
13. 3(b)(i)3 marksPlot a scatter graph of charge against result number on the grid opposite.
14. 3(b)(ii)2 marksHow do these results suggest that charge is quantized?
15. 3(b)(iii)1 markDeduce the value of the charge on the electron (in arbitrary units) implied by these data.
16. 4(a)(i)2 marksExplain the term 'drift velocity'.
17. 4(a)(ii)2 marksDefine the 'coulomb' and the 'volt'.
18. 4(a)(iii)4 marksFigure 4 shows electrons moving through a cross section of a wire. Show that the current, I, through the wire is given by I = nevA.
19. 4(b)(i)3 marksCalculate the velocity of the protons.
20. 4(b)(ii)3 marksCalculate the number density of protons in the beam.
21. 4(b)(iii)3 marksCalculate the number of protons hitting the target in 1 second.
22. 4(c)3 marksThe beam of protons in (b) is to be deflected around a curve of radius 2.0\text{ m}. If the magnetic field is perpendicular to the beam, calculate its field strength.
23. 5(a)(i)2 marksDefine 'magnetic flux density' and the 'tesla'.
24. 5(a)(ii)3 marksSketch the magnetic flux pattern due to a long straight wire carrying a current, and state the formula for the flux density, B, at a distance, r, from the wire.
25. 5(a)(iii)3 marksFigure 5 shows two long parallel wires, both of length l, separated by a distance r, carrying currents I_1 and I_2 in opposite directions. Show that the force between the two wires is given by…
26. 5(b)(i)4 marksCalculate the current through the wire.
27. 5(b)(ii)2 marksThe sensitivity of the balance is 0.1 \times 10^{-6}\text{ N}. Calculate the minimum current detectable using this balance.
28. 5(c)(i)3 marksCalculate the minimum number of turns per unit length that must be used.
29. 5(c)(ii)3 marksCalculate the total length of wire required.
30. 6(a)(i)1 markExplain why the scales on the axes are logarithmic rather than linear.
31. 6(a)(ii)1 markWhat value does the graph give for the open loop gain of the op-amp.?
32. 6(b)(i)1 markUse the graph to determine its bandwidth.
33. 6(b)(ii)2 marksDraw a circuit diagram to show how the non-inverting amplifier could be constructed.
34. 6(b)(iii)1 markWrite the formula for the gain of this amplifier.
35. 6(b)(iv)2 marksState the ratio of the feedback resistance to resistance of the input resistor in this non-inverting amplifier.
36. 6(c)2 marksUsing your answer to (a) above determine the maximum input voltage to the op-amp. if it is not saturated.
37. 6(d)(i)3 marksFind the potential at the non-inverting terminal of the op-amp in Figure 8.
38. 6(d)(ii)4 marksIn the dark the resistance of the light-dependent resistor (ldr) is 400\text{ k}\Omega. Find the potential at the inverting terminal in this situation and use this value to explain why the light emitting diode (led)…
39. 6(e)3 marksThe led in the circuit is rated 2.4\text{ V}, 25\text{ mA}. A protective resistor has to be connected in series with it so that it does not burn out. What is the value of this resistance?
40. 7(a)(i)1 markName an item found in the home which is controlled by a microprocessor.
41. 7(a)(ii)1 markState the function of the microprocessor in the item you have named.
42. 7(a)(iii)2 marksState TWO benefits resulting from the use of microprocessors.
43. 7(b)(i)3 marksIdentify the logic gates shown in Figure 9 and write out their respective truth tables.
44. 7(b)(ii)3 marksDraw the truth table for the entire circuit shown in Figure 9 and state its function.
45. 7(c)(i)1 markWrite the truth table for the circuit.
46. 7(c)(ii)3 marksDraw the logic circuit which uses only NAND gates and a single led to indicate logic 1 output.
47. 7(c)(iii)1 markWhat single logic gate is the circuit in (c)(ii) equivalent to?
48. 7(d)(i)2 marksState which diodes conduct when terminal X is positive with respect to terminal Y.
49. 7(d)(ii)3 marksThe input terminals X and Y are connected to the secondary coil of an ideal transformer. The primary coil contains 22000 turns and is connected to a 220\text{ V}_{\text{r.m.s.}} alternating supply. The input to the…