Question

Charge on an electron is $1.6\times 10^{-19}$ coulombs. No of electron passing through the wire per second on flowing of 1 ampere current through the wire
A. $0.625\times 10^{-19}$
B. $1.6\times 10^{19}$
C. $1.6\times 10^{-19}$
D. $0.625\times 10^{19}$

Answer 1

Hint: As this is a conceptual oriented question. We have to think from the basic principles and properties of current. Current across a loop is given by the charges passing by the cross sectional area of the conductor per unit time. The SI unit for current is ampere (A).
Also,
From definition of ohm's law: current flowing through a conductor is directly proportional to voltage drop across it.
As per the given data,
Charge on 1 electron is $1.6\times 10^{-19}$
Current passing through the wire is 1 ampere

Formula used:
Current, $I=\dfrac{Q}{t}$
Total charge, $Q=e_{n}\times e_{c}$

Complete answer:
By the basic definition of current it is the flow of charge carriers (electrons) passing through a cross sectional area of the wire in unit time period.
Mathematically:
\[I =\dfrac{Q}{t}\]
Where,
$I = current$
Q = charge passing through the wire
 t = time
The SI unit of current is ampere (A). 1A of current can be elaborated as 1 coulomb of charge passing through the cross sectional area of wire in 1 sec of time.
$1A= \dfrac{Q}{1s}$
$1A=Q$
$Q=e_{n}\times e_{c}$ (1)
Where,
$e_{c} =$ Charge on single electron
$e_{n}=$ No of electrons
By considering the derived value of Q in equation (1) and rearranging it,
$e_{n}= \dfrac{1}{1.6\times 10^{-19}}$

\[e_{n}= 0.625\times 10^{19} electrons\]

In electrolytes (ionic solutions), current is carried by both positive and negative ions. If a potential difference is applied, the positive ions will be attracted to the lower electric potential whereas the negative ions will be attracted to the higher electric potential. The positive and negative ions move in opposite directions, and the current flow is the sum of the magnitudes of the two individual currents.

So, the correct answer is “Option D”.

Note:
Go through the questions carefully, don't be in a hurry while investing time in reading or else you can make mistakes in the sign of the option. Basic current formula is needed here just don’t go for ohm's Law definition of current.