a student connect voltmeter in series and meter in parallel in a circuit.what Will be it's result?
Both a voltmeter and ammeter actually measure current as their measuring technique. The voltmeter has a high (ideally infinite, though certainly not infinite in practice) resistance, so if placed parallel in a circuit, very little current will go through it and most will go through the component to which it is parallel. An ammeter has very little resistance (ideally 0 Ohms, though not actually in practice), so it will not have a significant voltage drop across it when place in series with the components. If a student connect voltmeter in series he'll break the circuit and he'll see zero value. If a student connect meter in parallel he'll see zero value cause the current won't go through the meter.