CAPE Physics Unit 2 · 2019 · Paper 2

25 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)(i)2 marksDefine the term 'volt'.
2. 1(a)(ii)3 marksDefine the term 'coulomb' and state its relationship to the elementary physical unit of charge.
3. 1(b)5 marksIn the equation for Coulomb's law, F = Q₁Q₂ / (4πε₀R²), state the meaning of EACH symbol and its corresponding SI unit.
4. 1(c)4 marksA +100 µC and a test charge of -5 µC are 3 mm apart. Calculate the forces between them.
5. 1(d)(i)3 marksFor those electrons which are ejected at right angles to the lower plate, calculate the MAXIMUM initial energy, in joules, they can have if none of them reach the upper plate which has a voltage of –3 V with respect to…
6. 1(d)(ii)3 marksDetermine the MAXIMUM initial velocity of the electrons in (d)(i).
7. 1(d)(iii)5 marksCalculate the acceleration of the electrons in (d)(i).
8. 1(e)(i)3 marksDraw a tangent to the graph in Figure 2 and measure the angle of ejection.
9. 1(e)(ii)1 markRead off the MAXIMUM height reached from the lower plate.
10. 1(e)(iii)1 markRead off the distance travelled parallel to the plate before being re-absorbed.
11. 2(a)3 marksBriefly explain what is a light dependent resistor (LDR).
12. 2(b)5 marksShow that the bridge is balanced when R_L = R₁R₃ / R₂.
13. 2(c)(i)7 marksUse the graph to determine numerical values for b and R₀.
14. 2(c)(ii)1 markUse the equation given in (c) to determine an expression for R_L in terms of R₀ and I.
15. 2(c)(iii)1 markR_dark is defined as the resistance of the LDR when the light intensity, I ≤ 0.01 lux. Determine the threshold value of R_dark using the equation derived in (c)(ii).
16. 2(c)(iv)3 marksUsing the graph in Figure 4, determine the threshold value for R_dark.
17. 2(d)4 marksDetermine the value for I, the light intensity being measured.
18. 2(e)4 marksExplain why it is desirable to make V_B (the supply to the Wheatstone bridge) as small as practicable.
19. 2(f)2 marksState ONE example of a practical application of an LDR and briefly describe its operation.
20. 3(a)10 marksWith the aid of a fully labelled diagram, describe how X-rays are produced. Your description should include an explanation of why BOTH single line and continuous spectra are generated in this process.
21. 3(b)(i)4 marksOn the grid provided in Figure 5, plot a graph of relative intensity versus combined thickness. Draw your best smooth curve through the points.
22. 3(b)(ii)2 marksFrom the graph plotted in (b)(i), determine the thickness of lead which will reduce the intensity of the X-ray beam by 95%.
23. 3(b)(iii)5 marksBased on the result obtained in (b)(ii), calculate a value for µ_lead, the linear absorption coefficient of lead in m⁻¹.
24. 3(c)3 marksA metal Y has a linear absorption coefficient which is 0.25 µ_lead. Show that the thickness of Y required to produce the same attenuation as T_L cm of lead is 4 T_L.
25. 3(d)6 marksCalculate its wavelength, in metres.