1. The problem statement, all variables and given/known data A DC milliammeter has a full-scale deflection of 10 mA and a resistance of 50 Ω. How would you adapt this to serve as a voltmeter with a full-scale deflection of 150 V? Comment on whether this voltmeter would be suitable for accurately measuring the potential difference across a resistor of about 100 kΩ carrying a current of about 1 mA. Answers: 14 950 Ω in series. 2. The attempt at a solution R = V / I = 150 / 10 * 10-3 = 15 000 Ω. Less the given 50 Ω = 14 950 Ω are required for this milliammeter to serve as a voltmeter. However, why should it be applied in series? Voltmeters are applied in parallel. For the second part, shouldn't voltmeters have large resistances? And in this case the resistor has 100 000 Ω. I would say that this voltmeter wouldn't be suitable to accurately measure the PD across this resistor.