Question

How many electrons flow when a current of 5 amp is passed through a cell for 200 sec?

• A. \( 9.65 \times 10^{21} \)
• B. \( 1.60 \times 10^{21} \)
• C. \( 3.12 \times 10^{21} \)
• D. \( 6.24 \times 10^{21} \)

Hint:

To find the number of electrons, use the formula \( \text{Number of electrons} = \frac{Q}{e} \), where \( e \) is the elementary charge.

Answer 1

The Correct Option is D

Step 1: Using the formula for charge.
The total charge \( Q \) is given by: \[ Q = I \times t \] Where: \[ I = 5 \, \text{A}, \quad t = 200 \, \text{sec}. \] Thus, the total charge is: \[ Q = 5 \times 200 = 1000 \, \text{C}. \] Step 2: Using the formula for the number of electrons.
The number of electrons is calculated using the formula: \[ \text{Number of electrons} = \frac{Q}{e} \] Where \( e = 1.602 \times 10^{-19} \, \text{C} \) is the charge of a single electron. Substituting the values: \[ \text{Number of electrons} = \frac{1000}{1.602 \times 10^{-19}} = 6.24 \times 10^{21}. \] Step 3: Conclusion.
The correct answer is (D) \( 6.24 \times 10^{21} \).