Q. An ammeter reads 0.90 A when connected in series with a silver voltmeter that deposits 2.60 g of silver in 40 min. By what percentage is the ammeter reading is correct? Atomic weight of silver = 108 and 1 F=96500 C?
A) 5%
B) 7%
C) -5%
D) -7%
Explanation
(d) $m = zq = \frac{E}{F}It = \frac{M}{pF}It\ \ or\ I = \frac{mpF}{Mt}$
$\therefore{\ I}^{'} = \frac{2.60 \times 1 \times 96500}{108 \times (40 \times 60)} = 0.968$ A
% error in reading of ammeter
$= \left( \ \frac{I - I^{'}}{I^{'}} \right) \times 100 = \left( \ \frac{0.90 - 0.986}{0.968} \right) \times 100$
$= - 7\%$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.