The end of a battery is 4 volt and it`s internal resistance is 1.5 ohm . It`s potential difference is measured by a voltmeter of resistance 1000ohm. Calculate the percentage error in reading of emf shown by voltmeter.

Here emf is 4 volts ,r=1.5ohm ,R =1000ohm Current=e/(R+r),=4/1001.5 =0.00399. The p.d. across the voltmeter is. V=.00399/1000=3.99. Percentage error =e-v/e×100 =4-3.99/4×100 =0.25 percent