Question

The current flowing in a copper voltameter is 1.6 A. The number of Cu ⁺⁺ ions deposited at the cathode per minute are
1. 1.5 × 10²⁰
2. 3 × 10²⁰
3. 6 × 10²⁰
4. 1 × 10¹⁹

Answer 1

Correct Answer - Option 2 : 3 × 10²⁰

CONCEPT:

Electric current:

• The flow of electric charges through a conductor constitutes an electric current.
• Quantitatively, electric current in a conductor across an area held perpendicular to the direction of flow of charge is defined as the amount of charge flowing across that area per unit time i.e.,

\(⇒ {\rm{Electric\;curernt\;}}\left( {\rm{I}} \right) = \frac{{{\rm{Electric\;charge}}\;\left( {\rm{Q}} \right)}}{{{\rm{Time\;}}\left( {\rm{t}} \right)}}\)

• SI unit of current is ampere and it is denoted by the letter A. 

EXPLANATION:

Given - Current (I) = 1.6 A

• The amount of charge flowing across that area,

⇒ Q = current passed × time(sec)

⇒ Q = it = 1.6 × 60 = 96 C

• Total charge = Number of ions neutralised(n) × valency(v) × electon charge(e)
• Let n be the number of Cu ^{+ 2} ions, then

\(⇒ n = \frac{Q}{{v\; \times \;e}} = \;\frac{{96}}{{2\; \times \;1.6\; \times \;{{10}^{ - 19}}}} = 3\; \times \;{10^{20}}\;\)