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10 marksElectrical Circuits

CAPE Physics Unit 2 · May/June 2022 · Paper 2 · Question 1(b)

A circuit contains resistors connected in series and parallel, as shown in Figure 1. The circuit includes a 9 V power supply and various resistors with specified values, including a variable resistor R_L.

Calculate the current I_L through the variable resistor R_L, when R_L has a value of 30 Ω.

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Other parts of this question

  1. 1(a)(i)Draw a circuit diagram showing THREE resistors, R1, R2 and R3, placed in series connected to a power supply. On your diagram, label the voltages and the…[4 marks]
  2. 1(a)(ii)Using the diagram in (a)(i), derive the formula for the effective resistance of the THREE resistors in series.[6 marks]
  3. 1(c)(i)Complete Column 3 in Table 1.[2 marks]
  4. 1(c)(ii)On the grid provided in Figure 2 on page 9, plot a graph of I_L versus [1 + (R_L / 6)]^-1. Draw the line of best fit through the points.[4 marks]
  5. 1(c)(iii)Use the graph in (c)(ii) to determine the value of I_E.[4 marks]

More practice: the rest of this paper · more Electrical Circuits questions · all CAPE Physics Unit 2 past papers