Question

why high resistance box is connected in series to convert a galvanometer into voltmeter​

Answer 1

Answer:

A high resistance is used in series because it makes total net resistance more high hence it draws no current from circuit and all of the current goes through the element across which voltage is to be measured hence more accurate value is obtained.

Answer 2

Explanation:

To convert a given galvanometer into a voltmeter of range 'V' volts, a high resistance is connected in series with the galvanometer so that on applying a potential difference of 'V' volts across (R + Ro) the current Io, will flow through the galvanometer.