You should first count all the valence electrons. Then draw the central atom and single bonds to the rest (then go from there)
N2 + 3H2 -----> 2NH3
3 mol 2 mol
When 3 mol H2 react completely 2 mol NH3 are formed.
Answer:
A switch
Battery or cell
Resistor
Rheostat
Appliance or load such as bulb
connecting wires.
Jockey
Inductor
Capacitor
Meter bridge
Potentiometer
Voltimeter
Ammeter
Galvanometer