(a) What is least count of voltmeter ?
(b) In a voltmeter there are 20 divisions between the '0' mark and 0.5 V mark. Calculate its least count.

Explanation

(a) The minimum potential difference measured by a voltmeter between the two given terminals is called the least count of that voltmeter.
(b) Two given marks of the voltmeters = 0 and 0.5 V
Potential difference`=0.5-0=0.5 V`
No. of divisions between these two marks = 20
Least count `= (0.5)/(20) =(5)/(20xx10) =(1)/(40)=0.025` volts