A potentiometer wire of length 20 m has a resistance of 50 ohms. It is connected in series with a resistance box and a 5 V storage cell. If the potential gradient along the wire is 0.5 mV/cm, what is the resistance unplugged in the box?

MCQs on electric current, ohms law and its limitations, electrons drift and resistivity origin, various materials resistivity, electrical energy and power, resistivity temperature dependence, resistors combination, cells, emf and internal resistance, kirchoffs law, potentiometer, wheatstone and meter bridges.