Circuits - Series and Parallel
Q4.
(a) A student is given three resistors of resistance 3.0 , 4.0 and 6.0 respectively.
(i) Draw the arrangement, using all three resistors, which will give the largest resistance.
(ii) Calculate the resistance of the arrangement you have drawn.
R = 3.0 + 4.0 + 6.0 = 13
(iii) Draw the arrangement, using all three resistors, which will give the smallest resistance.
(iv) Calculate the resistance of the arrangement you have drawn.
1/R = 1/3.0 + 1/4.0 + 1/6.0 = (4.0 + 3.0 + 2.0)/12 = 9.0/12 = 0.75
R = 1/0.75 = 1.3
(5)
(b) The three resistors are now connected to a battery that provides a potential difference of 12V, as shown in the diagram below.
(i) Calculate the total resistance in the circuit.
1/R = 1/3.0 + 1/6.0 = 1/2.0
Rparallel = 2.0
RTotal = 2.0 + 4.0 = 6.0
(ii) Calculate the voltage across the 6.0 resistor.
(4)
(Total 9 marks)