Q. The current flowing in a copper voltmeter is $3.2\ A.$ The number of copper ions $(Cu^{2 +})$ deposited at the cathode per minute is
A) $0.5 \times 10^{20}$
B) $1.5 \times 10^{20}$
C) $3 \times 10^{20}$
D) $6 \times 10^{20}$
Explanation
(d) Charge supplied per minute $= 3.2 \times 60 = 192\ C$
Charge $2e$ liberates one $Cu^{+ 2}$ ion
$\therefore$ No of $Cu^{+ 2}$ ion liberate by $192\ C$
$= \frac{192}{2e} = \frac{192}{2 \times 1.6 \times 10^{- 19}} = 6 \times 10^{20}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.