CAPE Physics Unit 2 · 2018 · Paper 2

33 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 marksComplete Column 3 (ln R) in Table 1.
2. 1(b)4 marksUsing an appropriate scale, plot a graph of ln R vs T on the grid provided in Figure 1, and draw the line of best fit through the points.
3. 1(c)4 marksThe equation relating absolute temperature and resistance is R = R₀ exp(-β T). Use this equation and your graph to find the value of β.
4. 1(d)2 marksIdentify the type of thermometric device used in the investigation and justify your answer.
5. 1(e)3 marksState THREE differences between the resistivity of this conductor and that of most metallic conductors.
6. 2(a)4 marksState the meaning of the acronym LDR, and briefly explain its operation.
7. 2(b)2 marksComplete Columns 3 and 4 of Table 2 (log₁₀ R and log₁₀ Iᵥ).
8. 2(c)4 marksOn the grid provided in Figure 2, plot a graph of log₁₀ R against log₁₀ Iᵥ and draw the line of best fit through the points.
9. 2(d)3 marksUse your graph from (c) to find the resistance of the LDR at a luminous intensity of 200 cd.
10. 2(e)2 marksIf the switching circuit turns on the floodlights whenever the voltage at its input falls below 7.5 volts, what should the value of R be?
11. 3(a)(i)1 markWrite the exponential decay equation for radioactive materials.
12. 3(a)(ii)2 marksIdentify the decay constant in the equation in (a)(i) and state the units in which it is usually quoted.
13. 3(b)(i)3 marksOn the grid provided in Figure 4, plot a graph of count rate versus elapsed time, and draw a best smooth curve through the points.
14. 3(b)(ii)1 markDraw the tangent to the curve at the point where t = 0 and produce the tangent to intersect the t-axis.
15. 3(b)(iii)1 markRead off the value of t at the point of intersection.
16. 3(c)1 markIt can be shown that the half-life is 0.69τ where τ is the value of t at the point of intersection with the tangent. Calculate the half-life using this formula.
17. 3(d)2 marksDetermine the half-life by directly reading off from your graph and suggest a reason for any discrepancy between this value and the value calculated in (c).
18. 3(e)4 marksIf the initial sample contained 50 grams of the radioisotope at the start of the experiment, determine the quantity remaining after 4 hours.
19. 4(a)(i)2 marksDescribe the conditions in the atmosphere which lead to a lightning strike and state the electrical property of the strike that makes it dangerous to natural and man-made structures.
20. 4(a)(ii)2 marksDefine the term 'breakdown' and state ONE condition under which breakdown is likely to occur.
21. 4(a)(iii)3 marksDescribe the functional properties of lightning rods and explain how they work to protect structures on the ground.
22. 4(b)2 marksOn Figure 5, sketch the forces F₆ and F₁₈ on the third charge of +10 μC due to the +6 μC and the -18 μC charges respectively.
23. 4(c)3 marksCalculate the magnitude of EACH of the forces, F₆ and F₁₈.
24. 4(d)3 marksDetermine a value for the NET vertical force on the +10 μC charge.
25. 5(a)6 marksState THREE differences between the properties of an ideal operational amplifier and a real operational amplifier, giving typical values for EACH property stated.
26. 5(b)(i)3 marksSketch and label all the important features of ONE period of the output waveform when the amplitude Vₐ = 0.2 V.
27. 5(b)(ii)4 marksSketch and label all the important features of ONE period of the output waveform when the amplitude Vₐ = 2.0 V.
28. 5(c)2 marksState the value of the voltage at Pin 2 in Figure 6 on page 22. Give ONE reason why it has this value.
29. 6(a)3 marksDescribe the phenomenon of photoelectric emission.
30. 6(b)(i)3 marksDefine work function and state its unit of measurement.
31. 6(b)(ii)2 marksDefine cut-off wavelength and state its unit of measurement.
32. 6(c)(i)4 marksLight of wavelength λ is incident on a polished metal surface. Derive an expression for the maximum speed of the photoelectrons ejected.
33. 6(c)(ii)3 marksCalculate the maximum speed of the ejected photoelectron when λ = 100 nm, if the metal is tin and has a work function of 5.5 eV.