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

A. I and IV only
B. II and III only
C. III and IV only
D. I, II and III only
E. I, III and IV only

Correct Answer:

Option A – I and IV only

Explanation

Converting an ammeter to a voltmeter involves increasing the resistance of the ammeter. 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.