Explain how will you compare the e.m.f’s of two cells by a potentiometer.

Explain the principle of a potentiometer. How will you compare the e.m.f. of two primary cells by using potentiometer? Explain with proper circuit diagram.

Define e.m.f of a cell. How can you compare the e.m.f of the cells using potentiometer.

Direction. In the follwing questions, a statement of assertion is followed by a statement of reason. While answering a question, you are required to choose the correct are out of the given four responses and mark it as (A). If both assertion and reason are true and reason is the correct explanation of the assertion, (B) if both assertion and reason are true but reason is not correct explanation of the assertion. (C) if asssertion is true, but reason if false, (D) if both assertion and reason are false Assertion : To compare the e.m.fs of two cells using a potentiometer, the e.m.f. of the cell in auxillary circuit must be greater than the e.m.fs of both the cells. Reason : The area of cross-section of the wire should be uniform and current through the wire should always be kept constant.

Which one will you prefer to measure em.f of a cell, a potentiometer or a voltmeter?