In an open device, current through it is 

In an open device, the current through it is zero and the voltage is unknown

Important:

Short Circuit: It is an electrical circuit that allows a current to travel along an unintended path with zero or very low electrical impedance. This results in an excessive amount of current flowing into the circuit.

Ideally, it has zero resistance, hence high current will flow and no voltage drop across the terminals.

Open Circuit: It is a circuit where no current flows. Any circuit which does not have a return path to flow current is an open circuit.

It has infinite resistance, hence no current will flow.

Short circuit and open circuit can be represented as shown in the figure.