A 12V dc supply with negligible internal resistance is connected to two resistors R1=10kΩ and R2=5kΩ in series. A voltmeter of internal resistance Rv=50kΩ is used to measure the potential difference across R1.
(i) Calculate the potential difference across R1 when no measuring instrument is connected.
(ii) Draw a circuit diagram showing the voltmeter connected across R1 and determine the reading shown by the voltmeter.
(iii) Compute the percentage error introduced in the measurement due to the finite resistance of the voltmeter.
(iv) Comment quantitatively on how the error changes if a voltmeter of 500kΩ is used instead of 50kΩ.