Question

The specific charge of an electron is

• A. \( 1.8 \times 10^{-19} \, \text{C/kg} \)
• B. \( 1.67 \times 10^{-19} \, \text{C/kg} \)
• C. \( 1.8 \times 10^{11} \, \text{C/kg} \)
• D. \( 6.67 \times 10^{11} \, \text{C/kg} \)

Hint:

The specific charge of an electron is a constant \( \frac{e}{m} = 1.8 \times 10^{11} \, \text{C/kg} \).

Answer 1

The Correct Option is C

Step 1: Specific charge of electron.
The specific charge of an electron is the ratio of its charge to its mass. Mathematically, it is given by: \[ \text{Specific charge} = \frac{e}{m} \] where \( e = 1.6 \times 10^{-19} \, \text{C} \) is the charge of an electron, and \( m = 9.11 \times 10^{-31} \, \text{kg} \) is the mass of the electron.
Step 2: Calculation.
Substituting the values: \[ \frac{1.6 \times 10^{-19}}{9.11 \times 10^{-31}} = 1.8 \times 10^{11} \, \text{C/kg} \] Step 3: Elimination.
- (A) \( 1.8 \times 10^{-19} \, \text{C/kg} \): Incorrect.
- (B) \( 1.67 \times 10^{-19} \, \text{C/kg} \): Incorrect.
- (C) \( 1.8 \times 10^{11} \, \text{C/kg} \): Correct.
- (D) \( 6.67 \times 10^{11} \, \text{C/kg} \): Incorrect.
Step 4: Conclusion.
Therefore, the specific charge of an electron is \( 1.8 \times 10^{11} \, \text{C/kg} \).