Question

104. A voltmeter of 998 ohms resistance is connected to
a cell of emf 2 volts, having internal resistance of 2
ohms, The error in measuring emf will be :-
(1) 4 x 10-1V
3) 4*10-3v
(2) 2 x 10-3V
volen (3) 4 × 10-3V
(4) 2 x 10-1V​

Answer 1

Answer: 4*10^-3 volts

Explanation:

EMF of cell = 2 V

R= 998 ohm , r = 2 ohm

Current in the circuit ( I ) = EMF/ R+r

= 2 v / 998 + 2 ohm = 2/1000 amp.

thus, current = 2*10^-3 amp.

potential difference across the voltmeter = IR = 2 * 10^-3 * 998 = 1.996 v

so, actually the voltmeter across the cell which was supposed to read 2V , instead of this, it will read 1.996 V.

so error = E-V/E = 2-1.996/2 = 0.002 OR 2 * 10^-3 V (Ans)

thank you so much , I Hope that I was able to make you understand the Answer, if not, then I am deeply sorry .