Question

I attached the voltmeter in series and found ammeter reading is always showing zero how will you explain that

Answer 1

Case1: if the Voltmeter is connected in series first and ammeter in series next to supply,so effective impedance offered to supply will be very high, so current flowing through both meters will be in the order of milli amps.

No damage to both meters.

Case2: if the Ammeter is connected first in parallel with supply,next Voltmeter is connected next to it in series

Impedance offered bAmmeter to supply is very low, so high current flow through it, because of high heating, ammeter damags, but the Voltmeter is safe, because only few milli amps flow through it,