Assertion A potentiometer is preferred over that of a voltmeter for measurement of emf of a cell
Reason potentiometer does not draw any current from the cell.

Options

A. Both assertin and reason are true and reason is the correct explanation of assertion
B. Both assertion and reason are true but reason is not the correct explanation of assertion
C. Assertion is true but reason is flase
D. Both assertion and reason are false

Answer

A

Explanation

When a voltmeter is connected across the two terminals of a cell, it draws small curent from the cell, so it meausures terminal ptoential differecne between the two terminals of the cell whi8ch is lalways less than the emf of the cell on the other hand when a potnetiometer is uses for the measurement of emf of cell it doies not draw nay current from the cell Hence, it accurateluy measures the emf of cell. Thus a potentiometer is prefferred over a voltmeter.