find the current through a resistor of 2.0ohm if the p.d across it is 0.5v ??

Voltage (potential difference) across any component = (current) x (resistance)0.5 volt = (current) x (2 ohms)Divide each side by 2 ohms :Current =  0.5 / 2  =  0.25 Ampere = 250 mA