WAEC - Physics (1995 - No. 51)
Which of the following statements are not true of a moving-coil milliammeter? I. It can be used to measure alternating current II. It has a linear scale III. It can be adapted to read higher values of currents IV. A resistor connected in parallel with the milliammeter would convert it to a voltmeter
I and IV only
II and III only
III and IV only
I, II and III only
I, III and IV only
Paliwanag
Converting an ammeter to a voltmeter involves increasing the resistance of theammeter. This is done by adding a high resistance in series with the ammeter. Also, A moving coil meter indicates the average (mean) of a varying current through it, which is zero for AC. For this reason moving-coil meters are only usable directly for DC, not AC. Hence, I and IV are false.